Self-adaptive speed control method and system for descending of agricultural implement

Abstract

The invention discloses a self-adaptive speed control method and system for descending of an agricultural implement, belongs to the technical field of agricultural machinery, and solves the technical problems of low lifting efficiency and large ground contact impact of the agricultural implement. The method comprises the steps that the resistance change rate of resistance borne by the agricultural implement in the descending process is monitored in real time, the contact point of the agricultural implement and the ground is recognized according to the resistance change rate, and the descending stroke is divided into an idle stroke, the vicinity of the contact point and a working stroke according to the contact point; and respectively implementing different speed control strategies on the idle stroke and the working stroke. Therefore, efficiency is improved through quick descending in the idle stroke, impact generated when the agricultural implement enters the soil is reduced through slow descending at the contact point, the agricultural implement descends to the target tilling depth position at the working stroke speed after entering the soil, and the system has high self-adaptability and universality.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery technology, and more specifically, to an adaptive speed control method and system for the descent of agricultural implements. Background Technology

[0002] As the core power machinery in agricultural production, the electro-hydraulic lifting system of a tractor is a key component for connecting and controlling various agricultural implements (such as plows, harrows, and seeders). Existing electro-hydraulic lifting systems mainly achieve "position control," "resistance control," or "combined force and position control" of agricultural implements through position sensors (such as angle sensors) and force sensors (such as pull-rod pin-type force sensors).

[0003] Currently, mainstream electro-hydraulic lifting systems on the market generally employ control strategies of "constant speed throughout" or "segmented but fixed speed" when controlling the descent of agricultural implements. For example, the system may divide the descent process into two stages: "rapid descent" and "slow descent," but the switching point is usually based on a preset lifting arm angle or time, rather than the actual contact state between the agricultural implement and the ground.

[0004] This control method has the following obvious drawbacks: 1. Low efficiency: During the "idle stroke" phase before the agricultural machinery descends from its highest point to the ground, the system often adopts a slower descent speed due to concerns about impact, resulting in unnecessary time waste and reduced work efficiency.

[0005] 2. High impact and poor ride smoothness: When agricultural implements contact the ground at high speed, a violent impact is generated. This impact is not only transmitted to the tractor frame, causing the whole vehicle to vibrate and affecting the driver's comfort, but also puts additional dynamic loads on the engine, transmission system, hydraulic system and the agricultural implements themselves, accelerating the wear of parts and shortening the equipment's lifespan.

[0006] 3. Low level of intelligence: The existing system cannot dynamically adjust the descent speed near the contact point according to real-time working conditions such as soil hardness and type of agricultural machinery, resulting in a rigid control strategy.

[0007] In conclusion, existing technologies cannot effectively reduce the impact of agricultural machinery on the ground, improve driving smoothness, and enhance equipment reliability while ensuring operational efficiency. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art. The purpose of the present invention is to provide an adaptive speed control method for the descent of agricultural machinery, which can intelligently identify the contact point between the agricultural machinery and the ground, and dynamically adjust the descent speed according to the position of the contact point.

[0009] The second objective of this invention is to provide an adaptive speed control system for the descent of agricultural implements.

[0010] To achieve the first objective mentioned above, the present invention provides an adaptive speed control method for the descent of agricultural machinery. The method is characterized by real-time monitoring of the resistance change rate during the descent of the agricultural machinery, identifying the contact point between the agricultural machinery and the ground based on the resistance change rate, and dividing the descent stroke into an idle stroke, a stroke near the contact point, and a working stroke based on the contact point. Differentiated speed control strategies are then implemented for the idle stroke and the working stroke, respectively.

[0011] As a further improvement, the following steps are included: Step S1. Start descent: Select the descent mode and set the target tillage depth through the user control panel. After receiving the instruction, the ECU sends a control signal to the descent valve of the electro-hydraulic proportional control valve, and the agricultural implement begins to descend. Step S2. Data acquisition: During the descent of the agricultural implement, the ECU continuously reads the rotation angle value of the angle sensor and the resistance value F of the force sensor at millisecond intervals. Step S3. Intelligent contact point identification: During the descent of the agricultural implement, the ECU calculates the rate of change k of the resistance value F in real time, k=ΔF / Δt; When k is greater than the first threshold, it is determined that the working parts of the agricultural machinery begin to contact and cut into the soil; When k is greater than the second threshold for a set time, it is determined that the agricultural implement has made contact with the ground, and the position of the agricultural implement at this time is updated to the ground contact point P0. Step S4. Rapid descent during no-load travel: Based on historical contact point data, a contact point identification zone is preset, which corresponds to a portion of the travel before the agricultural implement touches the ground. When the agricultural implement has not entered the contact point identification zone or has entered the contact point identification zone but has not yet identified the ground contact point P0, it is determined that the agricultural implement is currently in no-load travel. During this stage, the ECU controls the electro-hydraulic proportional control valve to drive the agricultural implement to descend rapidly at a preset no-load travel speed. Step S5. Slow descent near the contact point. Once the ground contact point P0 is detected, the ECU immediately switches the control strategy and adjusts the descent speed to the preset contact point speed to drive the agricultural implement to descend slowly. Step S6. Adjusting the working stroke speed: When the agricultural implement continues to descend and its position has moved far away from the ground contact point P0 by a set distance, it is determined that the agricultural implement has smoothly completed its entry into the soil and entered the stable stage of the working stroke; at this time, the ECU adjusts the descent speed to the working stroke speed. Step S7. Reaching the target tillage depth: When the agricultural implement descends to the target tillage depth position, the ECU controls the electro-hydraulic proportional control valve to close, the lifting cylinder stops operating, and the descent process ends.

[0012] Furthermore, the millisecond period is 3-5ms.

[0013] Furthermore, the first threshold is greater than 20 × the second threshold.

[0014] Furthermore, the set time is >0.1s.

[0015] Furthermore, the contact point identification area extends from the ground contact point P0 to a height of 10cm-50cm above the ground.

[0016] Furthermore, the contact point speed is equal to 10%-30% of the idle travel speed.

[0017] Furthermore, the idle stroke speed > working stroke speed > contact point speed.

[0018] Furthermore, the set distance is 5-15cm.

[0019] To achieve the second objective mentioned above, this invention provides an adaptive speed control system for lowering agricultural implements, comprising a force sensor, a lifting cylinder, an oil tank, a hydraulic pump, a tractor, a CAN bus, a user control panel, an ECU, an angle sensor, a three-point suspension mechanism, agricultural implements, and an electro-hydraulic proportional control valve. The user control panel and ECU are installed in the tractor's cab. The user control panel is connected to the ECU via the CAN bus. The agricultural implement is mounted on the tractor via the three-point suspension mechanism. The tractor is equipped with an oil tank, a hydraulic pump, an electro-hydraulic proportional control valve, and a lifting cylinder that drives the three-point suspension mechanism to lift. The oil tank is sequentially connected to the hydraulic pump, the electro-hydraulic proportional control valve, and the lifting cylinder via oil pipes. The force sensor and angle sensor are installed in the three-point suspension mechanism. The ECU is electrically connected to the hydraulic pump, the electro-hydraulic proportional control valve, the force sensor, and the angle sensor. The ECU controls the descent speed of the agricultural implement according to the aforementioned adaptive speed control method for agricultural implement descent.

[0020] Beneficial effects Compared with the prior art, the present invention has the following advantages: 1. A ground contact point intelligent identification method based on the rate of change of resistance (ΔF / Δt). Unlike existing technologies that rely on switching at fixed positions or times, this invention dynamically and accurately identifies the actual contact point P0 between agricultural machinery and the ground by real-time monitoring and analysis of the rate of change of force sensor signals. This is the prerequisite and foundation for subsequent differentiated speed control.

[0021] 2. Three-stage differentiated speed control strategy for the descent stroke. The descent process of agricultural machinery is clearly divided into three stages: idle stroke, near the contact point, and working stroke far from the contact point. An independent and calibrable descent speed (V_fast, V_slow, V_work) is set for each stage to simultaneously optimize work efficiency, driving smoothness, and equipment reliability.

[0022] 3. Slow descent control logic near the contact point. Upon detecting the contact point P0, the system immediately switches to an extremely low descent speed (V_slow) to buffer the impact generated when the implement enters the soil. This is crucial for protecting the equipment and improving comfort.

[0023] 4. Rapid descent control logic during idle travel. During the idle travel phase, when it is confirmed that the ground has not been touched, the maximum safe speed (V_fast) is used for descent, which significantly shortens non-operation time and improves overall work efficiency.

[0024] 5. Independent calibration function for speed parameters. Allows users or manufacturers to independently adjust the three speed parameters V_fast, V_slow, and V_work according to factors such as the type of agricultural implement and the operating environment, making the system highly adaptable and versatile. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a flowchart of the present invention.

[0026] Among them: 1-force sensor, 2-lifting cylinder, 3-oil tank, 4-hydraulic pump, 5-tractor, 6-CAN bus, 7-user control panel, 8-electronic control unit (ECU), 9-angle sensor, 10-three-point suspension mechanism, 11-agricultural implement, 12-electro-hydraulic proportional control valve. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments shown in the accompanying drawings.

[0028] See Figures 1-2An adaptive speed control system for lowering agricultural implements includes a force sensor 1, a lifting cylinder 2, an oil tank 3, a hydraulic pump 4, a tractor 5, a CAN bus 6, a user control panel 7, an ECU 8, an angle sensor 9, a three-point suspension mechanism 10, an agricultural implement 11, and an electro-hydraulic proportional control valve 12. The user control panel 7 and ECU 8 are installed in the cab of the tractor 5. The user control panel 7 is connected to the ECU 8 via the CAN bus 6. The agricultural implement 11 is installed on the tractor 5 via the three-point suspension mechanism 10. The tractor 5 is equipped with an oil tank 3, a hydraulic pump 4, an electro-hydraulic proportional control valve 12, and a lifting cylinder 2 that drives the three-point suspension mechanism 10 to lift. The oil tank 3 is connected to the hydraulic pump 4, the electro-hydraulic proportional control valve 12, and the lifting cylinder 2 in sequence via oil pipes. The force sensor 1 and angle sensor 9 are installed on the three-point suspension mechanism 10. The ECU 8 is electrically connected to the hydraulic pump 4, the electro-hydraulic proportional control valve 12, the force sensor 1, and the angle sensor 9.

[0029] Lifting cylinder 2: It is a double-acting hydraulic cylinder. The extension and retraction of its piston rod drives the three-point suspension mechanism 10, thereby realizing the lifting and lowering of the agricultural implement 11.

[0030] Electro-hydraulic proportional control valve 12: Receives PWM control signals from ECU8 and precisely adjusts the flow rate of hydraulic oil flowing into or out of lifting cylinder 2, thereby controlling the movement speed of agricultural implement 11.

[0031] Angle sensor 9: Installed at the lifting arm pivot, used to measure the lifting arm's rotation angle in real time, indirectly reflecting the ground clearance or tillage depth of the agricultural implement 11.

[0032] Force sensor 1: Installed at the pin of the pull rod, used to measure the soil resistance F experienced by the agricultural implement 11 during operation in real time.

[0033] Electronic Control Unit (ECU8): This is the core of the entire system. ECU8 acquires signals from angle sensor 9 and force sensor 1 in real time, performs calculations based on a preset control algorithm, and outputs corresponding PWM signals to electro-hydraulic proportional control valve 12. Simultaneously, it also receives instructions from the user control panel 7, such as target tillage depth and mode selection.

[0034] An adaptive speed control method for the descent of agricultural implements involves real-time monitoring of the resistance change rate of the agricultural implement 11 during its descent, identifying the contact point between the agricultural implement 11 and the ground based on the resistance change rate, and dividing the descent stroke into an idle stroke, a stroke near the contact point, and a working stroke based on the contact point. Differentiated speed control strategies are then implemented for the idle stroke and the working stroke.

[0035] Specifically, the following steps are included: Step S1. Start descent. The driver selects the descent mode and sets the target tillage depth through the user control panel 7. After receiving the instruction, the ECU8 sends a control signal to the descent valve of the electro-hydraulic proportional control valve 12, and the agricultural implement 11 begins to descend.

[0036] Step S2. Data acquisition: During the descent of the agricultural implement 11, the ECU8 continuously reads the rotation angle value of the angle sensor 9 and the resistance value F of the force sensor 1 at millisecond intervals.

[0037] Step S3. Intelligent identification of contact points: During the descent of agricultural implement 11, ECU8 calculates the rate of change k of resistance value F in real time, k=ΔF / Δt.

[0038] When k is greater than the first threshold, it is determined that the working parts (such as plowshares) of the agricultural implement 11 begin to contact and cut into the soil.

[0039] When k is greater than the second threshold for a set period of time, it is determined that the agricultural implement 11 has made contact with the ground, and the position of the agricultural implement 11 at this time (which can be calculated by the angle value of the angle sensor 9) is updated to the ground contact point P0; the first threshold and the second threshold can be calibrated according to the type of agricultural implement and soil conditions.

[0040] Step S4. Rapid descent during idle travel: Based on historical contact point data, a contact point identification zone S1 is preset. This contact point identification zone S1 corresponds to a portion of the travel before the agricultural implement 11 touches the ground. If the agricultural implement 11 has not entered the contact point identification zone S1 or has entered the contact point identification zone S1 but has not yet identified the ground contact point P0, it is determined that the agricultural implement 11 is currently in idle travel. During this stage, the ECU8 controls the electro-hydraulic proportional control valve 12 to drive the agricultural implement 11 to descend rapidly at a preset idle travel speed V_fast. The idle travel speed V_fast is calibrable and is usually set to the maximum safe descent speed allowed by the system to minimize the idle travel time and improve work efficiency.

[0041] Step S5. Slow descent near the contact point. Once the ground contact point P0 is detected, ECU8 immediately switches the control strategy, adjusting the descent speed to the preset contact point speed V_slow to drive the implement 11 to descend slowly. This distance is S2. The contact point speed V_slow is also calibrable and is usually set to a very low value. The purpose of this stage is to allow the implement 11 to complete the initial soil entry process at an extremely smooth speed, thereby minimizing the impact on the tractor 5 and the implement 11, improving driving smoothness, and protecting key components such as the engine and transmission system.

[0042] Step S6. Adjusting the working stroke speed: When the implement 11 continues to descend and its position has moved far away from the ground contact point P0 by a set distance, it is determined that the implement 11 has smoothly completed its entry into the soil and entered the stable stage of the working stroke. At this time, ECU8 adjusts the descent speed to the working stroke speed V_work. The working stroke speed V_work can also be calibrated, and is usually between V_fast and V_slow, which can ensure both work efficiency and maintain a stable working state.

[0043] Step S7. Reaching the target tillage depth: When the agricultural implement 11 descends to the target tillage depth position, the ECU8 controls the electro-hydraulic proportional control valve 12 to close, the lifting cylinder 2 stops operating, and the descent process ends.

[0044] In this embodiment, the millisecond period is 3-5ms, the first threshold is >20×the second threshold, the set time is >0.1s, the contact point identification area is from the ground contact point P0 to a height of 10cm-50cm above the ground, the contact point speed is equal to 10%-30% of the idle travel speed, the idle travel speed > the working travel speed > the contact point speed, and the set distance is 5-15cm.

[0045] The most fundamental difference between this invention and existing technologies lies in dividing the descent process into three independently calibrable stages: Idle travel speed (V_fast): Prioritizes efficiency and achieves the fastest speed.

[0046] Velocity near the contact point (V_slow): Smoothness is the goal, and the speed is the slowest.

[0047] Working distance from the contact point speed (V_work): Balancing efficiency and smoothness, the speed is moderate.

[0048] These three speed parameters can be independently calibrated and stored by users or manufacturers according to specific agricultural machinery models, common soil conditions, etc., giving the system extremely high flexibility and adaptability.

[0049] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. An adaptive speed control method for the descent of agricultural implements, characterized in that, By real-time monitoring of the resistance change rate of the agricultural implement (11) during its descent, the contact point between the agricultural implement (11) and the ground is identified based on the resistance change rate. The descent stroke is divided into idle stroke, near the contact point, and working stroke based on the contact point. Differentiated speed control strategies are implemented for the idle stroke and working stroke respectively.

2. The adaptive speed control method for the descent of agricultural machinery according to claim 1, characterized in that, Specifically, the following steps are included: Step S1. Start descent. Select the descent mode through the user control panel (7) and set the target tillage depth. After receiving the instruction, the ECU (8) sends a control signal to the descent valve of the electro-hydraulic proportional control valve (12), and the agricultural implement (11) begins to descend. Step S2. Data acquisition: During the descent of the agricultural implement (11), the ECU (8) continuously reads the rotation angle value of the angle sensor (9) and the resistance value F of the force sensor (1) at millisecond intervals. Step S3. Intelligent identification of contact points: During the descent of the agricultural implement (11), the ECU (8) calculates the rate of change k of the resistance value F in real time, k=ΔF / Δt; When k is greater than the first threshold, it is determined that the working parts of the agricultural implement (11) begin to contact and cut into the soil; When k is greater than the second threshold for a set time, it is determined that the agricultural implement (11) has made contact with the ground, and the position of the agricultural implement (11) at this time is updated to the ground contact point P0; Step S4. Rapid descent during empty travel: Based on historical contact point data, a contact point identification area is preset, which corresponds to a section of travel before the agricultural implement (11) touches the ground. When the agricultural implement (11) does not enter the contact point identification area or enters the contact point identification area but has not yet identified the ground contact point P0, it is determined that the agricultural implement (11) is currently in the empty stroke stage. During this stage, the ECU (8) controls the electro-hydraulic proportional control valve (12) to drive the agricultural implement (11) to descend rapidly at a preset empty stroke speed. Step S5. Slow descent near the contact point. Once the ground contact point P0 is identified, the ECU (8) immediately switches the control strategy and adjusts the descent speed to the preset contact point speed to drive the agricultural implement (11) to descend slowly. Step S6. Adjusting the working stroke speed: When the agricultural implement (11) continues to descend and the position of the agricultural implement (11) is far away from the ground contact point P0 set distance, it is determined that the agricultural implement (11) has smoothly completed entering the soil and entered the stable stage of the working stroke; at this time, the ECU (8) adjusts the descent speed to the working stroke speed. Step S7. Reaching the target tillage depth: When the agricultural implement (11) descends to the target tillage depth position, the ECU (8) controls the electro-hydraulic proportional control valve (12) to close, the lifting cylinder (2) stops operating, and the descent process ends.

3. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The millisecond period is 3-5ms.

4. The adaptive speed control method for the descent of agricultural machinery according to claim 1, characterized in that, The first threshold is greater than 20 × the second threshold.

5. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The set time is >0.1s.

6. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The contact point identification area extends from the ground contact point P0 to a height of 10cm-50cm above the ground.

7. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The contact point speed is equal to 10%-30% of the idle travel speed.

8. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The idle travel speed > the working travel speed > the contact point speed.

9. The adaptive speed control method for the descent of agricultural implements according to claim 1, characterized in that, The set distance is 5-15cm.

10. An adaptive speed control system for the descent of agricultural implements, characterized in that, The system includes a force sensor (1), a lifting cylinder (2), an oil tank (3), a hydraulic pump (4), a tractor (5), a CAN bus (6), a user control panel (7), an ECU (8), an angle sensor (9), a three-point suspension mechanism (10), agricultural implements (11), and an electro-hydraulic proportional control valve (12). The user control panel (7) and the ECU (8) are installed in the cab of the tractor (5). The user control panel (7) is connected to the ECU (8) via the CAN bus (6). The agricultural implements (11) are installed in the cab via the three-point suspension mechanism (10). The tractor (5) is equipped with an oil tank (3), a hydraulic pump (4), an electro-hydraulic proportional control valve (12), and a lifting cylinder (2) that drives the three-point suspension mechanism (10) to lift. The oil tank (3) is connected to the hydraulic pump (4), the electro-hydraulic proportional control valve (12), and the lifting cylinder (2) in sequence through oil pipes. The force sensor (1) and the angle sensor (9) are installed on the three-point suspension mechanism (10). The ECU (8) is electrically connected to the hydraulic pump (4), the electro-hydraulic proportional control valve (12), the force sensor (1), and the angle sensor (9). The ECU (8) controls the descent speed of the agricultural implement (11) using an adaptive speed control method for agricultural implement descent according to any one of claims 1-9.

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