Crop digging depth control system and control method based on ground penetrating radar

Abstract

A kind of crop digging depth control system and method based on ground penetrating radar belong to wisdom agricultural machinery field.System includes vehicle body module, excavating mechanism, ground penetrating radar, lifting mechanism and control module.Ground penetrating radar detects crop root system buried depth by relative time difference method, and target depth is calculated in combination with safety margin;Control module adopts fuzzy self-adaptive PID algorithm, dynamically adjusts control parameters according to target depth and actual depth deviation, drives electric push rod to adjust digging shovel into soil depth, and realizes closed-loop control.The present application can sense crop underground position in real time, automatically adapt to soil condition change and terrain undulation, effectively avoid over-shallow missed digging or over-deep damage, significantly improve harvesting completeness and reduce energy consumption, and is suitable for tuber crops harvesting.

Description

Technical Field

[0001] This invention belongs to the field of intelligent agricultural machinery technology, and relates to a crop digging depth control system and control method based on ground penetrating radar. Specifically, it relates to a control system and control method that uses ground penetrating radar to perform non-contact real-time detection of the underground depth of crops, and uses a closed-loop PID control method to accurately adjust the digging depth, thereby improving digging efficiency, reducing damage, and reducing energy consumption. Background Technology

[0002] In recent years, ground-penetrating radar (GPR) technology has been widely used in the field of engineering for underground structure detection, but its application in agricultural crop harvesting is still in its early stages. Existing harvesting techniques largely rely on mechanical adjustment or manual experience, such as mechanically limited depth adjustment, manual observation of soil leveling and adjustment, and contact or photoelectric detection. These existing technologies cannot accurately control the excavation depth in real time and have poor adaptability to changes in field soil, light, and environment.

[0003] Because crop grain setting depth often varies within the same plot of land, and the soil is uneven, digging too shallowly can lead to crop damage or missed areas, causing significant economic losses. Digging too deep, on the other hand, significantly increases machine traction resistance, leading to increased energy consumption, and causes a large amount of soil to enter the conveying and separating device, increasing the difficulty of subsequent sorting and machine wear. Especially when harvesting stem vegetables such as scallions, more precise control of digging depth is needed to ensure crop integrity and minimize soil disturbance. Therefore, a system and method are required that can adapt to complex field environments, measure the underground position of crops in real time, and precisely control the digging depth. Summary of the Invention

[0004] To address the shortcomings of the existing technologies, this invention proposes a crop digging depth control system and method based on ground-penetrating radar. It uses ground-penetrating radar technology to accurately detect underground crop roots and stems, and combines it with a PID control algorithm to achieve closed-loop depth adjustment. This solves the depth control problems caused by complex environments and soil undulations in the existing technologies, improves automation and adaptability, further enhances the self-adjustment performance of digging depth, and reduces crop damage, missed digging, and soil disturbance.

[0005] The crop digging depth control system based on ground-penetrating radar provided in this application adopts the following technical solution:

[0006] A crop digging depth control system based on ground-penetrating radar, characterized in that the system comprises:

[0007] The body module is used for the installation, support, and movement of the entire system.

[0008] Excavation equipment, including excavating shovels and conveying and separating devices, is used to perform soil excavation and crop separation operations;

[0009] The excavation depth adjustment mechanism, installed on the side of the excavation mechanism, is used to emit electromagnetic waves into the soil and receive reflected signals to obtain information on the burial depth of crop roots;

[0010] The lifting mechanism is movably connected to the vehicle body module and is used to drive the overall lifting of the excavating mechanism.

[0011] The control module includes a comparator, a fuzzy adaptive PID controller, and a feedback module. The comparator is used to compare the target digging depth with the actual digging depth and output an error signal. The fuzzy adaptive PID controller outputs control commands based on the error signal. The feedback module is used to collect the actual soil penetration depth of the digging mechanism and feed it back to the comparator, thus forming a closed-loop control system.

[0012] By adopting the above technical solution, the system employs a closed-loop control architecture. Ground-penetrating radar emits electromagnetic waves into the soil and receives reflected signals to extract information on the burial depth of crop roots. A comparator compares the set target excavation depth with the actual burial depth collected by the feedback module, outputting an error signal. A fuzzy adaptive PID controller calculates the control quantity based on the error signal, driving the overall lifting of the excavation mechanism through a lifting mechanism to achieve dynamic adjustment of the excavation depth. This solves the problems of low open-loop control accuracy, inability to sense the actual burial depth of crops, and difficulty in adapting to spatial variations in root burial depth inherent in traditional crop excavation equipment, avoiding crop damage or over-burial caused by fixed-depth excavation. It achieves closed-loop control of "detection-decision-execution-feedback"; it can adjust the excavation depth in real time according to the actual burial depth of the crop; and the use of a fuzzy adaptive PID algorithm improves the system's adaptability to changes in soil conditions and control accuracy.

[0013] Furthermore, the lifting mechanism consists of a multi-link and an electric push rod. The electric push rod drives the multi-link to move via an electronic control signal to adapt to changes in field terrain.

[0014] By adopting the above technical solution, the lifting mechanism uses a combination structure of a multi-link mechanism and an electric actuator. The electric actuator receives electrical control signals and drives the multi-link mechanism to perform motion conversion, realizing the lifting action of the excavating mechanism. This solves the problem of rigid lifting mechanisms struggling to maintain stable digging depth in uneven field terrain and overcomes the poor adaptability of single actuators. The multi-link structure has excellent terrain conformity capability; the electric actuator provides rapid response and precise control, enabling the system to adaptively adjust to terrain undulations and maintain a constant penetration depth.

[0015] Furthermore, the digging shovel is driven to move up and down by an electric push rod, which adjusts the digging shovel's depth in real time according to the instructions of the control module.

[0016] By adopting the above technical solution, the excavator shovel is directly driven up and down by an electric actuator. After receiving instructions from the control module, the electric actuator adjusts the shovel's depth through precise stroke control. This solves the problems of response lag, low adjustment accuracy, and difficulty in achieving closed-loop automatic control inherent in traditional hydraulic or mechanical adjustments. It achieves rapid, precise, and electronically controlled adjustment of the excavator shovel; the electric actuator has high positioning accuracy and can accurately execute the controller's fine-tuning instructions, improving depth control resolution.

[0017] Furthermore, the excavation depth adjustment mechanism consists of a ground-penetrating radar, an electric push rod, and a connecting rod; the electric push rod controls the ground-penetrating radar, which is located on the side of the excavation mechanism and is used to transmit high-frequency electromagnetic waves into the soil and receive echo signals reflected from underground targets.

[0018] By adopting the above technical solution, the electric push rod adjusts the spatial position of the ground-penetrating radar via a linkage, aligning the radar transmitting antenna with the soil profile to emit high-frequency electromagnetic waves and receive reflected echoes from different media interfaces. Root depth is then calculated through time-domain analysis. The radar height is adjusted according to crop planting patterns and soil conditions to ensure the optimal signal-to-noise ratio. Positioned to the side of the excavating mechanism, it enables advanced detection and allows sufficient response time for the control system. The linkage mechanism prevents rigid collisions between the radar and obstacles.

[0019] Furthermore, the control module includes a comparator, a fuzzy adaptive PID controller, and a feedback module; the comparator is used to compare the target digging depth with the actual digging depth and output an error signal, the fuzzy adaptive PID controller outputs control commands according to the error signal, and the feedback module is used to collect the actual soil penetration depth of the digging mechanism and feed it back to the comparator, thus forming a closed-loop control system.

[0020] By adopting the above technical solution, the control module is further defined as including a comparator, a fuzzy adaptive PID controller, a feedback module, and their interconnections. The comparator performs subtraction to generate a depth error signal; the fuzzy adaptive PID controller adjusts the control parameters online to solve the model uncertainty problem caused by the time-varying soil parameters; and the feedback module measures the position of the excavating mechanism.

[0021] The crop digging depth closed-loop control method based on ground-penetrating radar provided in this application adopts the following technical solution:

[0022] A closed-loop control method for crop digging depth based on ground-penetrating radar includes the following steps:

[0023] S1: Initialize the ground-penetrating radar and calibrate the initial parameters;

[0024] S2: Set the safe excavation margin δ safety ;

[0025] S3: Maximum burial depth Z of crop roots extracted by ground-penetrating radar crop With δ safety Calculate the target excavation depth H target ;

[0026] S4: Establish the nonlinear relationship between the electric actuator stroke and the digging depth, and fit the equation using a quadratic polynomial: ,in Dig deeper to reach the target. The shortened stroke of the electric actuator is represented by a, b, and c, which are fitting coefficients based on the target excavation depth H. target The actual displacement ΔL of the reverse electric actuator;

[0027] S5: Compare the current actual excavation depth with H target If the difference exceeds the preset error range, the control quantity is calculated by the fuzzy adaptive PID controller to drive the digging shovel depth adjustment mechanism to achieve closed-loop control.

[0028] By adopting the above technical solutions, the problems of discontinuous depth control, reliance on manual experience, and inability to adjust in real time according to crop distribution in traditional excavation operations have been solved, realizing automated control of excavation depth; forming a complete automated control process; enabling continuous monitoring and adjustment of excavation depth; reducing manual intervention and improving operational efficiency; and ensuring consistent excavation quality.

[0029] Furthermore, the target mining depth H mentioned in step S3 target The calculation methods include: using ground-penetrating radar to extract the maximum burial depth Z of crop roots. crop Combined with the preset safety excavation margin δ safety Calculate the target excavation depth H target The formula is: H target = Z crop +δ safety Z crop It is based on the root depth of crops measured by ground-penetrating radar, δ safety This is a safety margin determined based on soil type and crop species.

[0030] By adopting the above technical solutions and using a summation model of root burial depth + safety margin, the contradiction between "clearing up crops" and "reducing soil disturbance" can be resolved. The target depth can be adaptively adjusted for different crops (such as peanuts, potatoes, and carrots) and different soil conditions. Under the premise of ensuring a harvest rate of ≥98%, ineffective digging work is minimized, fuel or electricity consumption is reduced, and soil structure damage and microbial environment disturbance caused by excessive digging are reduced.

[0031] Furthermore, step S4 establishes a nonlinear relationship between the electric actuator stroke and the digging depth, combined with the current H...target The target stroke ΔL is calculated in reverse, and the electric actuator is controlled to shorten from the initial length L1 to the working length L2, satisfying L2 = L1 - ΔL, so as to achieve precise adjustment of the digging shovel's soil penetration depth.

[0032] By adopting the above technical solution, the control algorithm needs to output specific displacement commands for the actuator, rather than abstract depth values; at the same time, it needs to compensate for errors caused by mechanism backlash, deformation, etc. The abstract "depth control" is transformed into specific "stroke control," achieving precise matching of the electromechanical system; by actively shortening the stroke (rather than extending) the control strategy, the backlash effect of the lead screw drive can be eliminated; before executing closed-loop control, pre-positioning is performed through model calculations, shortening the closed-loop adjustment time and improving the system response speed.

[0033] Furthermore, in step S5, the fuzzy adaptive PID controller calculates the control quantity based on the mining depth error. Dynamically adjust the proportional coefficient K p Integral coefficient K i and differential coefficient K d and output control commands. Satisfying the relation The electric actuator is driven to adjust the depth of the excavator blade, ensuring that the actual excavation depth matches the target depth H. target Consistent.

[0034] By adopting the above technical solutions, the problems of random variations in soil resistance, such as encountering rocks, root entanglement, or sudden changes in soil density leading to system model uncertainty, and the difficulty of balancing speed and stability with fixed-parameter PID control, resulting in inconsistent digging depth oscillations, are solved. The system adjusts dynamic parameters in real time based on the magnitude and trend of the error; it responds quickly when the depth deviation is large, rapidly approaching the target; it transitions smoothly when approaching the target, avoiding overshoot; when encountering rocks or sudden changes in soil hardness, the system can quickly detect abnormal depth change rates and adjust the control strategy to maintain a constant depth; fuzzy logic can limit the accumulation of integral components when the error is large, preventing the actuator from entering the saturation region and improving system stability.

[0035] In summary, the present invention has at least one of the following beneficial technical effects:

[0036] (1) This invention uses ground-penetrating radar to actively emit electromagnetic waves into the soil and receive reflected signals. It extracts the maximum burial depth of crop roots in real time using the relative time difference method and scientifically calculates the target excavation depth based on the safety excavation margin. This fundamentally changes the traditional extensive operation mode of fixed-depth excavation or manual estimation of depth. The system can dynamically adjust the excavation depth according to the actual root distribution of crops in different areas, effectively avoiding crop omissions (fruit loss) caused by shallow excavation and root breakage and fruit damage caused by excessive excavation. It is particularly suitable for harvesting crops with uneven burial depths, such as tubers and rhizomes. It can achieve non-invasive and accurate detection of root burial depth and on-demand excavation, significantly improving the crop harvest integrity rate.

[0037] (2) The control module in this invention adopts a fuzzy adaptive PID controller, which can dynamically adjust the proportional coefficient, integral coefficient, and derivative coefficient according to the excavation depth error, and has a stronger parameter adaptive capability compared with traditional PID control. Combined with the feedback module, the closed-loop control system can compensate for the depth deviation caused by external disturbances such as soil texture changes, terrain undulations, and machine vibration in real time, ensuring that the actual excavation depth is always stable within the preset error range. At the same time, the lifting mechanism composed of multi-link and electric push rod can effectively adapt to uneven terrain in the field, ensure the stability of the angle of the excavator entering the soil, greatly improve the operational reliability and control accuracy of the system in complex farmland environments, and significantly enhance the robustness and adaptability of the system to complex working conditions.

[0038] (3) This invention establishes a quadratic polynomial nonlinear mapping model between the change in the electric actuator stroke and the digging depth, and uses an inverse calculation method to accurately calculate the target stroke of the electric actuator from the target digging depth, thus realizing a precise quantitative correspondence between digging depth and actuator displacement. This method overcomes the problems of idle stroke, transmission clearance, and nonlinear error existing in traditional mechanical adjustment methods, making the adjustment of the digging depth more precise and faster, with a small response delay, effectively improving the dynamic response characteristics and steady-state accuracy of depth control, and improving the control response speed and accuracy.

[0039] (4) The system of this invention supports the inversion calibration of the relative permittivity of the soil using known depth calibration objects during the initial operation stage, thereby determining the electromagnetic wave propagation speed, or directly calling preset empirical values ​​according to different soil types, so that the depth calculation of the ground penetrating radar can adapt to soil environments with different dielectric properties such as sandy soil, loam, and clay. This flexible calibration method not only ensures the accuracy of root burial depth detection, but also makes the system easy to apply to various soil conditions in different regions without modifying the hardware structure, thus expanding the applicability and versatility of the equipment. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of the present invention from a first angle.

[0041] Figure 2 This is a side view of the entire invention.

[0042] Figure 3 This is a schematic diagram of the excavation depth adjustment mechanism and lifting mechanism in this invention.

[0043] Figure 4 This is a schematic diagram of the ground-penetrating radar mechanism in this invention.

[0044] Figure 5 This is a schematic diagram of the ground-penetrating radar detection principle in this invention.

[0045] Figure 6 This is a schematic diagram of the closed-loop control method for crop digging depth based on ground-penetrating radar in this invention.

[0046] Figure 7 This is a block diagram illustrating the principle of the closed-loop control system for crop digging depth based on ground-penetrating radar in this invention.

[0047] Figure 8 This is a schematic diagram illustrating the relationship between the electric actuator stroke and the digging depth in this invention.

[0048] In the diagram: vehicle body module 100, wheel 101, frame 102, crossbeam 103, excavation mechanism 200, excavation shovel 201, conveying and separating device 202, excavation depth adjustment mechanism 300, ground penetrating radar 301, electric push rod 302, connecting rod 303, lifting mechanism 400, first hinge seat 401, mounting connecting rod 402, second hinge seat 403, electric push rod 404, control module 500. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings and specific examples. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention. This embodiment uses cabbage as an example, but the invention is equally applicable to other leafy vegetable crops with similar color characteristics.

[0050] like Figure 1-2 As shown, the crop digging depth control system based on ground penetrating radar consists of a vehicle body module 100, a digging mechanism 200, a digging depth adjustment mechanism 300, and a lifting mechanism 400. The vehicle body module 100 is a mobile carrier, and the lifting mechanism 400 connects the vehicle body module 100 and the digging depth adjustment mechanism 300. The digging depth adjustment mechanism 300 is installed on the frame crossbeam.

[0051] like Figure 3As shown, in the digging depth adjustment mechanism 300 and the lifting mechanism 400, the electric actuator controls the lifting and lowering of the digging shovel. When the machine moves in the field, if it encounters potholes or changes in ridge height, the sensor provides immediate feedback and then controls the height adjustment accordingly. In the digging mechanism 200, the digging shovel 201 is the core operating component, which is connected to the conveying and separating device 202. The digging shovel 201 is installed via a sliding connection and is driven up and down by the electric actuator. The digging depth adjustment mechanism 300 converts the horizontal or inclined thrust of the electric actuator 404 into the vertical lifting force of the digging shovel 201 through the connecting rod 402; the effective arm length of the electric actuator determines the sensitivity and stroke range of the depth adjustment. By pre-setting the trigonometric function mapping relationship between the connecting rod length and the rotation angle, the controller can accurately convert the calculated target depth command into the pulse control quantity of the electric actuator.

[0052] like Figure 4 As shown, in the digging depth adjustment mechanism 300, the ground-penetrating radar 301 is mounted on a bracket on the side of the digging shovel 201. It transmits high-frequency electromagnetic waves into the soil non-contactly and receives reflected signals. Due to the significant difference in dielectric constant between root crops (high water content) and the surrounding soil, the radar echo spectrum can clearly show the depth position of the crop.

[0053] like Figure 5 As shown, the basic principle of ground-penetrating radar (GPR) detection is that the GPR emits high-frequency pulsed electromagnetic waves downwards. The electromagnetic waves encounter two key impedance abrupt changes along their propagation path, generating reflected echoes, thus yielding the time difference.

[0054] like Figure 6 The diagram illustrates the steps of the closed-loop control method for crop digging depth based on ground-penetrating radar (GPR) of this invention. Through time-difference analysis of radar echoes, absolute burial depth extraction unaffected by vehicle undulations is achieved, and real-time adjustment is ensured through a closed-loop cycle.

[0055] like Figure 7 As shown, this invention proposes a closed-loop control system for excavation depth, which uses ground-penetrating radar sensing information as a priori input and achieves precise adjustment of excavation depth through closed-loop control.

[0056] The system includes a target setting module, a sensing module, an adder, a comparator, a controller, an actuator, a controlled object, and a feedback module. The target setting module is used to set a safe excavation margin δ to ensure that the excavation process does not damage the crop root system or underground structure. The sensing module uses ground-penetrating radar to detect the distribution of crop roots and extract the maximum burial depth information Z of the crop roots. 植物 The adder is used to convert the ground-penetrating radar depth information Z... 植物 The target excavation depth H is generated by superimposing the safety excavation margin δ. 目标 The comparator is used to determine the target mining depth H.目标 The actual digging depth z(t) obtained from the feedback module is compared with the actual digging depth z(t), and the digging depth error e(t) is output. The controller adopts a fuzzy adaptive PID control algorithm, dynamically adjusts the proportional coefficient Kp, integral coefficient Ki, and derivative coefficient Kd according to the error e(t), and outputs control commands.

[0057] The actuator is an electric excavator (204), which drives the excavating mechanism to move under the action of the controller's output signal, thereby changing the depth of the excavator head's penetration into the soil. The controlled object is the depth of the excavator head's penetration into the soil, and its actual displacement is detected in real time by a displacement sensor and returned as a feedback signal to the comparator, forming a closed-loop control system. Through the above closed-loop control method, adaptive adjustment of the excavation depth based on ground-penetrating radar information is realized, improving operational safety and control accuracy.

[0058] like Figure 6 and Figure 7 As shown, this system employs integrated ground-penetrating radar sensing technology, utilizing the reflection characteristics of radar waves at different media interfaces to simultaneously extract the location of the land surface and underground crops in a single scan. The system processor executes the following detailed calculation steps:

[0059] Step 1: Acquisition and preprocessing of radar echo signals. Ground-penetrating radar transmits high-frequency pulsed electromagnetic waves downwards. These electromagnetic waves encounter two key impedance abrupt changes along their propagation path, generating reflected echoes:

[0060] 1. Air-soil interface (surface): Due to the significant difference in dielectric constants between air and soil, a strong reflection peak is generated, and its two-way travel time is recorded as follows.

[0061] 2. Soil-crop interface (target): Electromagnetic waves continue to propagate downwards into the soil, producing a second reflection peak when they encounter tubers with high water content. The two-way travel time is recorded.

[0062] Step 2: Calculate the relative compaction depth of the crop in the soil.

[0063] Since the radar is mounted in front of the excavator and suspended in the air, we need to calculate the depth of the crop relative to the ground surface, using "phase"...

[0064] The "time difference method" eliminates the impact of fuselage turbulence on altitude.

[0065] Depth of the crop top from the ground surface The calculation formula is as follows:

[0066] · : Indicates the time difference of an electromagnetic wave traveling to and from the soil layer;

[0067] · The speed at which electromagnetic waves propagate in the soil medium.

[0068] Step 3: Online inversion of soil dielectric constant and wave velocity correction

[0069] speed of electromagnetic waves in soil Relative permittivity of soil The relevant formula is:

[0070] (c is the speed of light, approximately 3 × 10^8 m / s)

[0071] To improve accuracy, the system can use a metal calibration object of known depth during the initial operation phase. Perform inversion calibration; or preset empirical values ​​based on soil type (sand, clay).

[0072] Combining the above two formulas, the final calculation model for crop seed setting depth is as follows:

[0073] Note: This algorithm utilizes the time difference principle to automatically compensate for changes in the radar antenna's height above the ground caused by rack undulations (i.e., and They may increase or decrease simultaneously, but the difference will be... It is only related to the depth within the soil, so it can achieve bump-resistant detection without the need for a laser rangefinder.

[0074] Step 4: Setting and Executing the Target Mining Depth

[0075] Set the safe digging margin for the excavator shovel The target depth of the excavator tip into the soil. :

[0076]

[0077] Step 5: PID Closed-Loop Control

[0078] The calculated The deviation e(t) is generated by comparing it with the actual depth fed back by the current excavation electric actuator.

[0079] The PID algorithm is used to drive the movement of the excavator's electric linear actuator.

[0080] It is the difference between the "target depth" calculated by the radar and the "current depth" of the electric actuator.

[0081] It refers to the voltage or command sent to the electric actuator.

[0082] like Figure 8As shown, the data from the ground-penetrating radar is fed back to the control system, involving changes in elevation. H1 represents the target digging depth (expected value) measured by the ground-penetrating radar. H2 represents the actual vertical displacement (actual displacement) of the electric actuator. To eliminate nonlinear errors, this embodiment preferably uses a quadratic fitting model, calculating the electric actuator displacement based on the ground-penetrating radar detection depth. In the figure, L1 is the initial length of the electric actuator (reference position), and L2 is the working length of the electric actuator (corresponding to the length when the digging shovel enters the soil and reaches the bottom of the crop). H1 is the vertical displacement of the digging shovel from the initial position to the working position (i.e., the actual digging depth).

[0083] Step 1: Depth Data Acquisition and Target Setting

[0084] Ground-penetrating radar (401) transmits pulses in real time and receives echoes to calculate the actual root depth Zcrop of the current crop. Based on operational requirements, the target excavation depth H1 = Zcrop is set.

[0085] Note: If a safety margin is required, set H1 = Zcrop + ;

[0086] Step 2: Establish the kinematic mapping equations

[0087] Invoke the multinomial fitting feature model stored in the controller:

[0088] in, This is the shortened stroke that the electric actuator should produce;

[0089] Step 3: Reverse Calculation of Target Travel

[0090] The controller substitutes the acquired Zcrop data into the fitting equation and uses the quadratic formula or inverse function to calculate the target stroke.

[0091] Step 4: Calculate the target length L2

[0092] Given that the initial length (fully extended position) of the electric actuator is a constant L1, the target working length that the electric actuator should achieve is: .

[0093] like Figure 7 and Figure 8 As shown, this invention employs depth conversion logic based on shortened stroke of the electric actuator. When the ground-penetrating radar (401) detects a crop root depth of Zcrop, the system uses it as the target value H1. Since the excavating electric actuator (204) drives the excavating shovel (301), the relationship between its stroke and depth exhibits non-linear characteristics. This invention establishes a quadratic polynomial fitting model through pre-calibration: During the control process, the controller acquires real-time data on the change in the push rod from its initial length. Shorten to working status The displacement deviation is controlled to ensure that the excavator tip is numerically equal to Zcrop, thereby achieving adaptive precision excavation.

Claims

1. A crop digging depth control system based on ground-penetrating radar, characterized in that, The system includes: The body module (100) is used for the installation, support and movement of the entire system; The excavation mechanism (200) includes an excavation shovel (201) and a conveying and separating device (202) for performing soil excavation and crop separation operations; The excavation depth adjustment mechanism (300) is installed on the side of the excavation mechanism and is used to emit electromagnetic waves into the soil and receive reflected signals to obtain information on the burial depth of crop roots. A lifting mechanism (400) is movably connected to the vehicle body module (100) and is used to drive the excavator mechanism (200) to lift as a whole. The control module (500) includes a comparator, a fuzzy adaptive PID controller and a feedback module. The comparator is used to compare the target digging depth with the actual digging depth and output an error signal. The fuzzy adaptive PID controller outputs control commands according to the error signal. The feedback module is used to collect the actual soil penetration depth of the digging mechanism and feed it back to the comparator, thus forming a closed-loop control system.

2. The crop digging depth control system based on ground-penetrating radar according to claim 1, characterized in that: The lifting mechanism (400) consists of a multi-link (402) and an electric push rod (404). The electric push rod (404) drives the multi-link (402) to move through an electric control signal to adapt to changes in field terrain.

3. The crop digging depth control system based on ground-penetrating radar according to claim 1, characterized in that: The digging shovel (201) in the digging mechanism (200) is driven to move up and down by an electric push rod (404), and the electric push rod (404) adjusts the depth of the digging shovel into the soil in real time according to the instructions of the control module (500).

4. The crop digging depth control system based on ground-penetrating radar according to claim 1, characterized in that: The excavation depth adjustment mechanism (300) consists of a ground-penetrating radar (301), an electric push rod (302), and a connecting rod (303); the electric push rod (302) controls the ground-penetrating radar (301), which is located on the side of the excavation mechanism and is used to transmit high-frequency electromagnetic waves into the soil and receive echo signals reflected by underground targets.

5. The crop digging depth control system based on ground-penetrating radar according to claim 1, characterized in that: The control module (500) includes a comparator, a fuzzy adaptive PID controller, and a feedback module. The comparator is used to compare the target excavation depth with the actual excavation depth and output an error signal. The fuzzy adaptive PID controller outputs control commands according to the error signal. The feedback module is used to collect the actual soil penetration depth of the excavating mechanism and feed it back to the comparator, thus forming a closed-loop control system.

6. A closed-loop control method for crop digging depth based on ground-penetrating radar, utilizing the control system described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Initialize the ground-penetrating radar and calibrate the initial parameters; S2: Set the safe excavation margin δ safety ; S3: Maximum burial depth Z of crop roots extracted by ground-penetrating radar crop With δ safety Calculate the target excavation depth H target ; S4: Establish the nonlinear relationship between the electric actuator stroke and the digging depth, and fit the equation using a quadratic polynomial: ,in Dig deeper to reach the target. The shortened stroke of the electric actuator is represented by a, b, and c, which are fitting coefficients based on the target excavation depth H. target The actual displacement ΔL of the reverse electric actuator; S5: Compare the current actual excavation depth with H target If the difference exceeds the preset error range, the control quantity is calculated by the fuzzy adaptive PID controller to drive the digging shovel depth adjustment mechanism to achieve closed-loop control.

7. The closed-loop control method for crop digging depth based on ground-penetrating radar according to claim 6, characterized in that: The target excavation depth H mentioned in step S3 target The calculation methods include: using ground-penetrating radar to extract the maximum burial depth Z of crop roots. crop Combined with the preset safety excavation margin δ safety Calculate the target excavation depth H target The formula is: H target = Z crop +δ safety Z crop It is based on the root depth of crops measured by ground-penetrating radar, δ safety This is a safety margin determined based on soil type and crop species.

8. The closed-loop control method for crop digging depth based on ground-penetrating radar according to claim 6, characterized in that: Step S4 establishes a nonlinear relationship between the electric actuator stroke and the digging depth, combined with the current H target The target stroke ΔL is calculated in reverse, and the electric actuator is controlled to shorten from the initial length L1 to the working length L2, satisfying L2 = L1 - ΔL, so as to achieve precise adjustment of the digging shovel's soil penetration depth.

9. The closed-loop control method for crop digging depth based on ground-penetrating radar according to claim 6, characterized in that: The fuzzy adaptive PID controller in step S5 calculates the control quantity based on the mining depth error. Dynamically adjust the proportional coefficient K p Integral coefficient K i and differential coefficient K d and output control commands. Satisfying the relation The electric actuator is driven to adjust the depth of the excavator blade, ensuring that the actual excavation depth matches the target depth H. target Consistent.

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