A method and system for accurately positioning rice seedlings

Abstract

The present application relates to the technical field of rice transplanting, and particularly relates to a precise positioning rice transplanting method and system. The present application realizes a turning radius of <=2m through a full-hydraulic four-wheel independent drive module, distributes torque in real time based on the depth of the mud feet, and maintains the stability of the deep mud field through intelligent suspension. Meanwhile, the present application controls the lifting of the auxiliary wheels through sensor data, triggers an audible and light alarm when the three-dimensional inclination sensor detects a lateral inclination angle >=15 degrees, and automatically reduces the speed to <=0.5m / s. In this process, the present application precisely controls the transplanting mechanism to complete the actions of taking, separating and transplanting the seedlings with a depth of 3-5cm through a HST stepless speed change mechanism in a speed range of 0.2-4m / s. Through the full-hydraulic four-wheel independent drive module and the liftable auxiliary wheel mechanism, the present application adjusts the distribution of power and the pressure of the ground contact, so that the rice transplanting machine can stably travel in a deep mud field with a mud foot depth exceeding 40cm, thereby effectively reducing the risk of getting stuck, and ensuring the continuity and efficiency of the operation.

Description

Technical Field

[0001] This invention relates to the field of rice transplanting technology, and in particular to a precise positioning method and system for rice transplanting. Background Technology

[0002] In mechanized rice planting operations, the passability and operational stability of the power chassis in deep muddy paddy fields are key technical challenges. Existing power chassis for rice transplanters used in paddy fields are designed and configured mainly for paddy field environments with general muddy depths. These chassis systems can meet basic operational needs under normal conditions.

[0003] When operating in deep muddy fields, the risk of existing chassis getting stuck increases significantly. Once stuck, the chassis often cannot effectively extricate itself using its own power. This is mainly because the deep mud causes uneven distribution of ground pressure and a significant decrease in adhesion. Conventional driving and extrication strategies are difficult to implement effectively in such extremely soft and low-bearing surface conditions. These frequent problems of getting stuck and difficult to extricate not only seriously hinder the continuity and efficiency of operations, but also increase the risk of equipment damage and operational safety.

[0004] Therefore, in response to the problem of chassis sinking and difficulty in getting out of deep muddy fields, this invention proposes a precise positioning method and system for rice transplanting. By integrating a new chassis system and transplanting method with fully hydraulic four-wheel independent drive, intelligent auxiliary wheel lifting, adaptive suspension adjustment and side rollover warning technology, the transplanter's ability to avoid sinking and getting out of trouble, driving stability and operation safety in muddy fields with a depth of more than 40 cm is improved. Summary of the Invention

[0005] In order to overcome the problem that the chassis of existing devices is prone to sinking and difficult to detach in deep muddy fields, this invention proposes a precise positioning method and system for rice transplanting.

[0006] The technical solution of this invention is: a method for precise positioning of rice transplanting, comprising the following steps: S1 uses a fully hydraulic four-wheel independent drive module to drive the rice transplanter chassis, and achieves a turning radius of ≤2m through four-wheel differential steering control; S2 distributes torque to the four wheels in real time based on the mud depth and maintains the stability of the chassis in fields with mud depth ≥400mm through an intelligent suspension system; S3 controls the raising and lowering of the auxiliary wheel of the rear wheel based on data from the distance sensor and humidity sensor; S4, based on three-dimensional tilt sensor data, monitors the vehicle tilt angle in real time. If the tilt angle is ≥15°, it will trigger an audible and visual alarm and automatically reduce the speed to ≤0.5m / s. S5, within a travel speed range of 0.2-4m / s, controls the rice transplanting mechanism through the HST continuously variable transmission mechanism to complete the actions of picking up, separating and transplanting rice seedlings, inserting the seedlings into the mud layer to a depth of 3-5cm.

[0007] Preferably, the differential steering includes independently controlling the speed of the four wheels via a hydraulic motor, while simultaneously monitoring the tire slippage rate in real time and using a PID control algorithm to distribute torque. When the depth of a single wheel sinking into the ground exceeds a threshold, the torque output difference of the other wheel is automatically increased to 1.5-2 times to form a forced traction torque.

[0008] Preferably, the rice transplanter chassis is equipped with a suspension system that links a three-stage adjustable shock absorber with a hydraulic cylinder. The system collects real-time data on the undulation of the ground surface using a field laser scanner. When the ground clearance is detected to be less than 400mm, the hydraulic pump is activated to raise the chassis to a safe height of 500mm. The system automatically switches to a low-damping mode in hard subsurface areas and a high-damping mode in deep mud areas.

[0009] Preferably, the raising and lowering of the auxiliary wheel is performed using an electric push rod with a response time of ≤0.5s.

[0010] Preferably, the control of the auxiliary wheel includes lowering the auxiliary wheel when the mud depth is >40cm or the soil shear strength is <15kPa. The auxiliary wheel uses a honeycomb aluminum floating plate to reduce the grounding pressure to 5-8kPa, and the wheel spacing of the auxiliary wheel can be adjusted within the range of 1000-1200mm.

[0011] As a preferred option, a precise positioning rice transplanting system includes: The fully hydraulic four-wheel independent drive module is used to achieve differential steering by independently controlling the speed of each wheel through hydraulic motors; The tooth profile of the paddy field wheel is optimized to increase the ground contact area to 0.2㎡ and the tooth inclination angle is 20°±2°. The intelligent suspension system is used to dynamically adjust the ground clearance to 400-500mm according to the undulations of the field surface; The rear wheel liftable auxiliary wheel mechanism is used to deploy when the mud depth is >40cm to reduce ground pressure; The rollover detection and warning module is used to trigger an audible and visual alarm and link the braking system when the vehicle body roll angle is greater than 15°. The rice transplanting module is used to complete the actions of picking up seedlings, separating seedlings, and transplanting them; The central controller processes sensor data and coordinates the actions of the HST continuously variable transmission and various actuators.

[0012] Preferably, the fully hydraulic four-wheel independent drive module includes four sets of hydraulic motors, each set of hydraulic motors independently drives one tire, the maximum output torque of the hydraulic motor is ≥800 N·m, and the system pressure is set to 20-25 MPa.

[0013] Preferably, the tooth-optimized paddy field wheel includes 24 trapezoidal teeth, the anti-mud adhesion coating on the wheel spoke surface is a polyurethane-based composite material, the wheel hub has 6 axial drainage channels with a diameter of 10mm inside, and wear-resistant hard alloy strips are welded to the outer circumference of the wheel rim.

[0014] Preferably, the rear wheel liftable auxiliary wheel mechanism includes a humidity sensor, which automatically lowers the auxiliary wheel to distribute gravity when the soil moisture content is >60%.

[0015] Preferably, the rollover detection and warning module includes a three-dimensional tilt sensor, a warning processor, and an automatic braking unit. The three-dimensional tilt sensor uses a gyroscope and accelerometer fusion detection. The warning processor calculates the real-time rollover risk index using a fuzzy PID algorithm. When the roll angle is greater than 15°, the driver's cab audible and visual alarm is activated. When the roll angle is greater than 20°, the automatic braking unit cuts off the power output of the HST continuously variable transmission through the clutch and triggers the parking hydraulic brake.

[0016] The beneficial effects of this invention are: This invention utilizes a fully hydraulic four-wheel independent drive module and a liftable auxiliary wheel mechanism to dynamically adjust the power distribution and ground pressure, enabling the rice transplanter to travel stably in deep muddy fields with a mud depth exceeding 40cm. This effectively reduces the risk of getting stuck, ensuring continuous operation and efficiency. Furthermore, when one tire becomes stuck in the mud, the system automatically increases the torque output of the other tire, creating a forced extrication torque. Combined with the liftable auxiliary wheels to distribute gravity, this significantly enhances the rice transplanter's self-rescue capability in extremely soft muddy fields, reducing the need for manual rescue.

[0017] This invention employs four-wheel differential steering control, reducing the turning radius to ≤2m, thereby improving maneuverability in field operations. Simultaneously, the adaptive dynamic transmission system adjusts torque distribution in real time to suppress tire slippage, ensuring chassis stability in deep mud environments. Furthermore, it adjusts suspension height and shock absorption damping in real time based on the undulations of the field surface, ensuring the chassis ground clearance is always ≥400mm. It automatically switches to the optimal mode in hard subgrade and deep mud areas, reducing the risk of bumps and sinking, and improving operational stability.

[0018] By monitoring the vehicle's attitude in real time with a three-dimensional tilt sensor, an audible and visual alarm is triggered and the speed is automatically reduced when the roll angle is ≥15°, and power is cut off and braking is applied when the roll angle is >20°, thereby significantly reducing the risk of rollover accidents and protecting the safety of personnel and equipment. Attached Figure Description

[0019] Figure 1 The diagram shown illustrates the workflow of this invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1 The present invention provides an embodiment of a method for precise positioning of rice transplanting, comprising the following steps: First, the rice transplanter chassis is driven by a fully hydraulic four-wheel independent drive module. The steering control of the four wheels is used to achieve a small turning radius of ≤2m. During the journey, the torque of the four wheels is dynamically distributed based on the real-time detection of the mud depth. The intelligent suspension system maintains the driving stability of the chassis in muddy fields with a depth of ≥400mm. At the same time, the rear auxiliary wheel is raised and lowered intelligently based on the data of the humidity sensor. When the mud depth is >40cm or the soil moisture content is >60%, the auxiliary wheel is automatically lowered to distribute the weight. The vehicle tilt angle is continuously monitored during the journey. When the tilt angle is ≥15°, an audible and visual alarm is triggered and the speed is automatically reduced to ≤0.5m / s. Finally, within the continuously variable transmission range of 0.2-4m / s, the HST continuously variable transmission mechanism precisely controls the transplanting mechanism to complete the actions of picking up, separating and planting seedlings, thereby ensuring that the seedlings are inserted into the mud layer to a depth of 3-5cm.

[0022] Furthermore, the four-wheel independent drive and differential steering significantly improve the passability and steering flexibility in deep muddy fields, while the adaptive torque distribution and intelligent lifting of the auxiliary wheels can effectively prevent the chassis from sinking and enhance its ability to get out of trouble. At the same time, the real-time tilt angle monitoring and automatic speed reduction mechanism greatly reduce the risk of rollover. The coordinated control of the continuously variable transmission and the planting mechanism ensures the unity of work efficiency and planting accuracy. Overall, this invention achieves a synergistic improvement in high passability, high safety and high work quality in deep muddy field environments.

[0023] The differential steering system includes independent control of the four wheel speeds via hydraulic motors, real-time monitoring of tire slippage rate, and torque distribution using a PID control algorithm. When the depth of a single wheel sinking into the ground exceeds a threshold, the torque output difference of the other wheel is automatically increased to 1.5-2 times to form a forced traction torque.

[0024] Furthermore, four independently controlled hydraulic motors drive the four tires respectively. The maximum output torque of each hydraulic motor is set to ≥800 N·m, and the system pressure is maintained within the range of 20-25 MPa. During the steering process, the central controller collects the rotation speed signal of each tire in real time and calculates the slip rate. When it is detected that a single tire is stuck in the mud and the slip rate exceeds the set threshold, the system immediately starts the PID control algorithm to dynamically adjust the flow distribution of the hydraulic motor, increasing the torque output of the other side to 1.5-2 times that of the stuck side, forming a forced escape torque difference. At the same time, the stuck tire automatically switches to a high-frequency intermittent drive mode to reduce continuous slippage. The duration of this torque difference is adaptively adjusted according to the tire sinking depth until the slip rate returns to a safe range. During this process, the four-wheel independent drive system communicates in real time with the three-dimensional tilt sensor through the CAN bus to ensure that the torque distribution process does not affect the vehicle stability. Ultimately, without adding any additional escape devices, the rice transplanter can autonomously escape from a single-sided deep-seated state simply through the intelligent adjustment of the power system.

[0025] Furthermore, the rice transplanter chassis is equipped with a suspension system that links three-stage adjustable shock absorbers with hydraulic cylinders. A laser scanner on the field surface collects real-time data on ground undulations and transmits it to the central controller. When the ground clearance is detected to be less than 400mm, the system immediately activates the hydraulic pump to raise the chassis to a safe height of 500mm. During the raising process, the shock absorbers automatically switch to high-damping mode to suppress vehicle sway. When operating in hard subsurface areas, the system automatically switches to low-damping mode after recognizing that the surface firmness meets the standard to improve ride smoothness. In deep mud areas, it maintains high-damping mode to enhance chassis stability. The suspension height adjustment uses closed-loop control, with distance sensors installed at the four corners of the chassis providing real-time feedback on ground clearance data to ensure adjustment accuracy does not exceed ±10mm. The system also features a manual priority mode, which can forcibly lock the suspension height when automatic adjustment fails. This suspension system, through dynamic adjustment, not only effectively avoids the risk of the chassis bottoming out but also significantly improves ride comfort and operational stability when operating in deep muddy fields.

[0026] Furthermore, the auxiliary wheel lifting mechanism uses an electric push rod for lifting. The push rod has a rated thrust of ≥3000N and a stroke of 200mm. The control system receives signals from the distance sensor and soil moisture sensor in real time. When the mud depth is detected to be >40cm or the soil moisture content is >60%, the central controller immediately sends a PWM control signal to the electric push rod, driving the push rod to complete the rapid extension of the auxiliary wheel from the retracted position to the working position within 0.5s. During the lifting process, the Hall sensor installed in the push rod provides real-time feedback of position information to form a closed-loop control, thereby ensuring that the final positioning accuracy of the auxiliary wheel reaches ±2mm. In an emergency, the push rod can be directly controlled via a button in the cab. The system adopts dual-channel CAN bus communication and redundant power supply design, thereby ensuring that lifting commands can still be reliably executed in complex field environments. This rapid response mechanism significantly improves the rice transplanter's ability to get out of trouble in case of sudden deep entrapment.

[0027] A precise positioning rice transplanting system includes: The fully hydraulic four-wheel independent drive module is used to achieve differential steering by independently controlling the speed of each wheel through hydraulic motors; The tooth profile of the paddy field wheel is optimized to increase the ground contact area to 0.2㎡ and the tooth inclination angle is 20°±2°. The intelligent suspension system is used to adjust the ground clearance to 400-500mm according to the undulations of the field surface; The liftable auxiliary wheel mechanism is used to deploy when the mud depth is >40cm to reduce grounding pressure; The rollover detection and warning module is used to trigger an audible and visual alarm and link the braking system when the vehicle body roll angle is greater than 15°. The rice transplanting module is used to complete the actions of picking up seedlings, separating seedlings, and transplanting them. The central controller processes sensor data and coordinates the actions of the HST continuously variable transmission and various actuators.

[0028] The optimized paddy field wheel has 24 trapezoidal teeth, the anti-mud adhesion coating on the wheel spoke surface is made of polyurethane-based composite material, the wheel hub has 6 axial drainage channels with a diameter of 10mm inside, and wear-resistant hard alloy strips are welded to the outer circumference of the wheel rim.

[0029] The liftable auxiliary wheel mechanism includes a humidity sensor and a distance sensor. When the mud depth is greater than 40cm or the soil moisture content is greater than 60%, the auxiliary wheel will automatically lower to distribute the weight.

[0030] The rollover prevention detection and early warning module includes a three-dimensional tilt sensor, an early warning processor, and an automatic braking unit. The three-dimensional tilt sensor uses a gyroscope and accelerometer fusion detection. The early warning processor calculates the real-time rollover risk index using a fuzzy PID algorithm. When the roll angle is greater than 15°, the driver's cab audible and visual alarm is activated. When the roll angle is greater than 20°, the automatic braking unit cuts off the power output of the HST continuously variable transmission through the clutch and triggers the parking hydraulic brake.

[0031] The system uses a three-dimensional tilt sensor to collect vehicle posture data in real time. It calculates the tilt angles of the X / Y / Z axes through a sensor fusion algorithm with a measurement accuracy of ±0.1°. The warning processor runs a fuzzy PID control algorithm to calculate a real-time rollover risk index by combining tilt angle data, driving speed, and ground slope. When a roll angle >15° is detected, the system immediately triggers the audible and visual alarm in the driver's cab, which in turn triggers a 120dB buzzer to sound and a red LED to flash. It also sends a speed reduction command to the HST continuously variable transmission via the CAN bus to limit the vehicle speed to a safe range. If the roll angle continues to increase to >20°, the system immediately cuts off the power output of the clutch and activates the parking hydraulic brake, while simultaneously locking all four wheels hydraulically within 0.3 seconds.

[0032] Furthermore, the present invention provides an embodiment for a conventional deep muddy field operation scenario: When the rice transplanter entered a paddy field with a mud depth of 45cm, the four-wheel independent drive system detected in real time that the slippage rate of the right rear wheel exceeded the preset threshold of 15%. The central controller immediately activated the differential escape program: First, based on the PID control algorithm, the system pressure of 20MPa was output to the hydraulic motor of the left front wheel, increasing its torque value from the base of 600N·m to 1080N·m, thereby forming a forced escape torque in the counterclockwise direction. At the same time, the right rear wheel switched to intermittent drive mode, thereby effectively reducing the mud agitation caused by continuous slippage. While the power system was adjusting, after receiving the measured data of 45.3cm from the mud depth sensor, the rear auxiliary wheel mechanism extended its electric push rod by 120mm within 0.48 seconds, allowing the two sets of 400mm diameter honeycomb aluminum auxiliary wheels to fully contact the ground, increasing the vehicle's ground contact area by 35% and the ground pressure. As the force decreased from 12 kPa to 7.8 kPa, the three-dimensional tilt sensor detected that the vehicle body tilted 12.3° to the left front due to the right rear wheel getting out of trouble. The anti-rollover detection and warning module activated the audible and visual alarm, but did not reach the 15° braking trigger threshold. The HST continuously variable transmission maintained the current operating speed of 2.1 m / s. The suspension system used the field surface data obtained by the laser scanner to control the hydraulic cylinder to increase the ground clearance of the chassis center from the initial 380 mm to 452 mm. At the same time, the damping coefficient of the shock absorber was adjusted to 18 N·s / mm to suppress the vehicle body sway. Throughout the process, the rice transplanting mechanism maintained a transplanting depth of 4.1 ± 0.2 cm within the speed fluctuation range of 2.03-2.15 m / s through the speed-depth coupling control algorithm, thereby ensuring that the angle of the seedling entering the mud was always controlled within the ideal range of 88°-92°.

[0033] Furthermore, the present invention provides an embodiment for a sudden, trapped escape scenario: When the right rear wheel suddenly got stuck in 50cm deep mud, the stuck side switched to high-frequency pulse drive mode (100ms drive / 50ms stop). At the same time, the hydraulic motor pressure of the left front, left rear and right front wheels was synchronously increased to 22MPa, and the output torque reached 1200N·m, thus forming a powerful compound extrication torque. Meanwhile, the two sets of rear auxiliary wheels were fully deployed within 0.5 seconds, and the honeycomb floating plate increased the vehicle's ground contact area to 0.35㎡, and the ground pressure dropped sharply from 15kPa to 6kPa. The anti-rollover detection and warning module monitored the vehicle body in real time and found that the vehicle body tilted 18.2° due to unilateral restriction. It immediately triggered the audible and visual alarm and limited the vehicle speed to 0.3m / s through the CAN bus. At this time, the suspension system automatically switched to ultra-high damping mode (25N·s / mm), and the hydraulic cylinder raised the chassis to a safe height of 480mm. After 8 seconds of torque optimization distribution, the vehicle successfully got out of trouble. During this period, the rice transplanting mechanism automatically disconnected the power transmission through the electromagnetic clutch to avoid damage to the rice seedling picking mechanism under abnormal working conditions.

[0034] This embodiment verifies the system's ability to coordinate power regeneration, emergency support, and safety protection under extreme vehicle stuck conditions, and the response time of all subsystems meets the design specifications.

[0035] Furthermore, the present invention provides an embodiment for a turning scenario on an extremely slippery paddy field ridge: When turning on a field ridge with a soil moisture content of 70%, the system automatically calculates the optimal speed difference between each wheel, thereby precisely controlling the turning radius to 1.8m. When the outer wheel has an increased probability of slipping due to the load, the system controls the torque of the outer wheel to increase by 30% and briefly reduces the speed of the inner wheel. At the same time, the anti-rollover detection and warning module maintains the body tilt angle within a safe range of 10° in real time, and the auxiliary wheels automatically adjust the extension range according to the steering angle. The lateral deviation of the body does not exceed 15cm during the entire steering process.

[0036] When the rice transplanter enters a slippery paddy field ridge with 70% soil moisture content at a speed of 2.4 m / s and turns, the system calculates the target speed of the four wheels in real time: the left front wheel accelerates to 58 rpm, the right front wheel decelerates to 42 rpm, and the rear wheel group maintains a base speed of 52 rpm, thereby accurately achieving a turning radius control of 1.78m. During the turning process, the load transfer causes the slip rate of the outer right front wheel to rise to 18%. The system immediately increases the torque of the right front wheel by 30% to 780 N·m and briefly reduces the speed of the inner left front wheel by 15% to balance the driving torque. The anti-rollover detection and warning module, by integrating data from the gyroscope and accelerometer, controls the tilt angle of the vehicle body in real time within the safe range of 9.8°-10.2°. When the instantaneous tilt reaches 11.5°, the steering correction torque is activated in advance, and the outer auxiliary wheel automatically adds 20mm of extension according to the steering angle, increasing its effective support area by 25%, thereby forming an anti-rollover reinforcement structure.

[0037] Throughout the steering process, the lateral offset of the vehicle body was verified to be 14.7cm using a laser rangefinder. The rice planting mechanism maintained a stable planting depth of 3-5cm within a speed fluctuation range of ±0.15m / s, verifying the system's ability to maintain steering accuracy under extreme adhesion conditions.

[0038] Through the above steps, the power distribution and ground pressure are dynamically adjusted by the fully hydraulic four-wheel independent drive module and the liftable auxiliary wheel mechanism, enabling the rice transplanter to drive stably in deep muddy fields with a mud depth of more than 40cm. This effectively reduces the risk of getting stuck, thus ensuring the continuity and efficiency of the operation and solving the problem of the chassis easily getting stuck and difficult to get out of the existing device in deep muddy fields.

[0039] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for precise positioning of rice transplanters, characterized in that, It includes the following steps: S1 uses a fully hydraulic four-wheel independent drive module to drive the rice transplanter chassis. It achieves a turning radius of ≤2m through four-wheel differential steering control. The differential steering includes independently controlling the speed of the four wheels through hydraulic motors, while monitoring the tire slippage rate in real time and distributing torque using a PID control algorithm. When the depth of a single wheel exceeds a threshold, the torque output difference of the other wheel is automatically increased to 1.5-2 times to form a forced escape torque. S2, based on the real-time distribution of torque to the four wheels according to the mud depth, maintains the stability of the chassis in fields with mud depth ≥400mm through an intelligent suspension system; wherein, the chassis of the rice transplanter is equipped with a suspension system with three-level adjustable shock absorbers linked to hydraulic cylinders, and collects the undulation data of the ground surface in real time through a field laser scanner. When the ground clearance is detected to be <400mm, the hydraulic pump is started to raise the entire chassis to a safe height of 500mm, and automatically switches to low damping mode in hard bottom areas and high damping mode in deep mud areas; S3, based on data from the distance sensor and humidity sensor, controls the raising and lowering of the auxiliary wheel of the rear wheel; wherein, the raiseable auxiliary wheel mechanism uses an electric push rod to raise and lower the auxiliary wheel, the raiseable auxiliary wheel mechanism includes a humidity sensor and a distance sensor, when the mud depth is >40cm or the soil moisture content is >60%, the auxiliary wheel is automatically lowered to disperse the gravity; the auxiliary wheel uses a honeycomb aluminum floating plate to reduce the ground pressure to 5-8kPa, and the wheel spacing of the auxiliary wheel can be adjusted within the range of 1000-1200mm; S4, based on three-dimensional tilt sensor data, monitors the vehicle tilt angle in real time. If the tilt angle is ≥15°, it triggers an audible and visual alarm and automatically reduces the speed to ≤0.5m / s. When the tilt angle is >20°, it cuts off the power output of the HST continuously variable transmission through the clutch and triggers the parking hydraulic brake. S5, within a travel speed range of 0.2-4m / s, controls the rice transplanting mechanism through the HST continuously variable transmission mechanism to complete the actions of picking up, separating and transplanting rice seedlings, inserting the seedlings into the mud layer to a depth of 3-5cm.

2. A precise positioning rice transplanting system, comprising a precise positioning rice transplanting method according to claim 1, characterized in that, Including: The fully hydraulic four-wheel independent drive module is used to achieve differential steering by independently controlling the speed of each wheel through hydraulic motors; The toothed paddy field wheel is optimized to increase the ground contact area to 0.2m. 2 And the gear tooth inclination angle is 20°±2°; The intelligent suspension system is used to adjust the ground clearance to 400-500mm according to the undulations of the field surface; The liftable auxiliary wheel mechanism is used to deploy when the mud depth is >40cm to reduce grounding pressure; The rollover detection and warning module is used to trigger an audible and visual alarm and link the braking system when the vehicle body roll angle is greater than 15°. The rice transplanting module is used to complete the actions of picking up seedlings, separating seedlings, and transplanting them; The central controller processes sensor data and coordinates the actions of the HST continuously variable transmission and various actuators.

3. The precise positioning rice transplanting system according to claim 2, characterized in that: The fully hydraulic four-wheel independent drive module includes four sets of hydraulic motors, each of which independently drives one tire. The maximum output torque of the hydraulic motor is ≥800 N·m, and the system pressure is set to 20-25 MPa.

4. The precise positioning rice transplanting system according to claim 3, characterized in that: The optimized paddy field wheel has 24 trapezoidal teeth, the anti-mud adhesion coating on the wheel spoke surface is made of polyurethane-based composite material, the wheel hub has 6 axial drainage channels with a diameter of 10mm inside, and wear-resistant hard alloy strips are welded to the outer circumference of the wheel rim.

5. The precise positioning rice transplanting system according to claim 4, characterized in that: The liftable auxiliary wheel mechanism includes a humidity sensor and a distance sensor. When the mud depth is greater than 40cm or the soil moisture content is greater than 60%, the auxiliary wheel will automatically lower to distribute the weight.

6. The precise positioning rice transplanting system according to claim 5, characterized in that: The rollover prevention detection and early warning module includes a three-dimensional tilt sensor, an early warning processor, and an automatic braking unit. The three-dimensional tilt sensor uses a gyroscope and accelerometer fusion detection. The early warning processor calculates the real-time rollover risk index using a fuzzy PID algorithm. When the roll angle is greater than 15°, the driver's cab audible and visual alarm is activated. When the roll angle is greater than 20°, the automatic braking unit cuts off the power output of the HST continuously variable transmission through the clutch and triggers the parking hydraulic brake.

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