Three-point linkage hydraulic attitude adjustment control system and method

Abstract

This invention relates to the field of agricultural equipment technology, and in particular to a hydraulic attitude adjustment control system and method for a three-point suspension device. The control system includes: a lifting cylinder with a lower pull rod hinged at one end and a lifting swing arm hinged at the other end; the other end of the lifting swing arm is connected to the agricultural machinery; a lateral leveling cylinder with a lower pull rod hinged at one end; a central upper pull rod cylinder with one end hinged to the upper part of a triangular fixed frame and the other end connected to the attachment point of the work implement; an angular displacement sensor installed at the hinge shaft of the lifting swing arm; and stroke sensors installed at the end of the central upper pull rod cylinder and at the single-sided lateral cylinder. The angular displacement sensor and stroke sensor are respectively connected to the vehicle's ECU. This invention solves the problem of existing systems having a single dimension of attitude adjustment and being unable to perform real-time closed-loop control of multi-dimensional attitude during operation, thereby improving the uniformity of tillage and operational stability under undulating farmland conditions.

Description

Technical Field

[0001] This invention relates to the field of agricultural equipment technology, and in particular to a hydraulic attitude adjustment control system and method for a three-point suspension device. Background Technology

[0002] The three-point suspension system is the core connecting and load-bearing component between agricultural machinery and various field implements. Tractors connect rotary tillers, plows, harrows, and other implements via the three-point suspension system. During operation, the suspension system controls the implements' ground clearance, lateral tilt angle, and pitch angle. The attitude control performance of the suspension system directly affects the flatness of the tilled land, the uniformity of sowing depth, and the evenness of soil tillage, making it a key factor determining the quality of farmland operations.

[0003] Currently, the three-point suspension systems widely used in China are still mainly traditional mechanical hydraulic suspension systems. These systems typically consist of a hydraulic pump, distributor, lifting cylinder, upper tie rod, and left and right lower tie rods. The basic working process is as follows: the operator controls the distributor valve core to reverse via a lever, allowing hydraulic oil to enter the lifting cylinder, driving the left and right lifting arms to swing synchronously, which in turn raises and lowers the lower tie rods, thus achieving the overall lifting or lowering of the implement. The upper tie rod is generally an adjustable-length rigid rod, and its length is manually adjusted before operation to set the implement's entry pitch angle. The lateral level of the implement is maintained by the mechanical positioning of the left and right limit rods, remaining essentially unchanged during operation. The overall system attitude setting relies on the operator's visual judgment and manual operation, while the lifting speed of the lifting cylinder is roughly controlled by the lever opening.

[0004] Because the lifting and lowering actions of the traditional three-point suspension system are driven synchronously by the left and right lifting cylinders, and the length of the upper tie rod and the left and right limit rods are set once before operation and remain unchanged, the system can only achieve the single function of lifting and lowering the implement during operation, and cannot adjust the lateral tilt and pitch attitude of the implement in real time. However, in actual farmland operations, there are common situations such as uneven ground, changes in soil drag, and the left and right drive wheels of the tractor not being on the same plane. The implement will tilt and pitch laterally as it moves with the terrain. When the implement tilts, due to its large working width, even a small tilt angle will cause a large height difference between the two ends, affecting the flatness and consistency of tillage depth. In addition, the traditional system lacks smooth speed control during lifting and lowering, resulting in large impacts; each cylinder branch also lacks independent overload protection, which can easily damage hydraulic components when encountering rocks or hard soil layers that cause a sudden increase in load. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a hydraulic attitude adjustment control system for a three-point suspension device that can simultaneously achieve lifting, lateral leveling, and pitch adjustment of machinery. This system solves the problem that existing systems have a single attitude adjustment dimension and cannot perform real-time closed-loop control of multi-dimensional attitudes during operation, thereby improving the uniformity of tillage and operational stability under undulating farmland conditions.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: In a first aspect, embodiments of the present invention provide a hydraulic attitude adjustment control system for a three-point suspension device, including a lifting cylinder, a lifting swing arm, a pull rod, a lateral leveling cylinder, a central upper pull rod cylinder, a triangular fixing frame, an angular displacement sensor, a stroke sensor, and a vehicle ECU; One end of the lifting cylinder is hinged to a pull rod, and the other end is hinged to a lifting swing arm. The other end of the lifting swing arm is connected to the agricultural machinery. One end of the lateral leveling cylinder is hinged to a pull rod. One end of the central upper pull rod cylinder is hinged to the upper part of the triangular fixed frame, and the other end is connected to the attachment point of the working implement. The angular displacement sensor is installed at the hinge shaft of the lifting swing arm, and the stroke sensor is installed at the end of the central upper pull rod cylinder and the single-sided lateral cylinder. The angular displacement sensor and the stroke sensor are respectively connected to the vehicle ECU.

[0007] Secondly, embodiments of the present invention also provide a hydraulic attitude adjustment and control method for a three-point suspension device, comprising the following steps: Pre-calibrate the working posture reference value, calibrate the instantaneous reading of the detection values ​​of the angular displacement sensor and the stroke sensor, convert them into the corresponding ground clearance, left and right tilt amount and pitch angle reference values ​​and store them; During field operations, three attitude data are collected simultaneously. The rotation angle of the lifting arm is collected by the angular displacement sensor and converted into the actual height of the implement above the ground. The extension and retraction displacement of the upper tie rod cylinder is collected by the stroke sensor installed at the end of the central upper tie rod cylinder and converted into the current pitch angle of the implement. The extension and retraction displacement of the lateral cylinder is collected by the stroke sensor installed at the lateral cylinder on one side and combined with the stroke data of the other side cylinder to perform difference calculation and calculate the current left and right lateral tilt deviation of the implement. The real-time calculated altitude data, left and right lateral tilt deviation data, and front and rear pitch angle data are compared with the pre-stored calibration reference attitude values ​​to determine the direction and magnitude of the deviation. When the real-time attitude deviates from the reference threshold range, a PWM proportional electronic control signal with a corresponding duty cycle is generated and sent to the solenoid coil of each control main valve to control the extension and retraction of the corresponding hydraulic cylinder to complete the attitude correction.

[0008] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: This invention features independently driven lifting cylinders, lateral leveling cylinders, and a central upper pull rod cylinder. These three sets of cylinders correspond to the three degrees of freedom: lifting, lateral leveling, and pitch adjustment. The lifting cylinder raises and lowers the lower pull rod via a lifting arm; the lateral leveling cylinder directly pulls the lower pull rod to change the left-right height difference; and the central upper pull rod cylinder adjusts the pitch angle by changing its own length. These three actions are independent of each other, achieving decoupled adjustment of the three degrees of freedom and solving the problem of single adjustment dimension. Furthermore, angular displacement sensors and stroke sensors are installed at the hinge shaft of the lifting arm, the end of the central upper pull rod cylinder, and the single-sided lateral cylinder, respectively. These three sensors synchronously collect height, pitch angle, and lateral tilt amount and transmit them to the vehicle ECU. The ECU processes the three attitude data simultaneously, compares them with preset thresholds, and outputs multiple PWM control signals to achieve synchronous detection and correction of multi-dimensional attitudes, solving the problem of inability to achieve synchronous closed-loop control. Furthermore, the independently hinged pull rod structure of the lateral leveling cylinder allows the lateral leveling force to be directly borne by the cylinder, rather than transmitted through a mechanical limit rod. Consequently, when the load on one side suddenly increases, the overload valve in this path independently releases pressure, preventing the impact load from being transmitted to other components and solving the problem of easy damage to components under lateral force. In summary, through the combined structure of three sets of independently driven cylinders, three synchronous sensors, and ECU closed-loop control, decoupling of degrees of freedom is achieved at the mechanical level, multi-posture synchronous perception is achieved at the detection level, and multi-path parallel adjustment is achieved at the control level. This collaborative approach addresses the technical problems existing in current systems from three levels: mechanical structure, sensor detection, and electronic control algorithm.

[0009] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0011] Figure 1 This is a schematic diagram of the system structure provided in an embodiment of the present invention; Figure 2 This is a hydraulic schematic diagram provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the system installation provided in an embodiment of the present invention; Figure 4 This is a flowchart provided by an embodiment of the present invention; In the diagram: 101. Left lateral leveling cylinder; 102. Left lower lever; 103. Right lower lever; 104. Right lateral leveling cylinder; 105. Right lifting cylinder; 106. Central upper lever cylinder; 107. Right lifting swing arm; 108. Left lifting swing arm; 109. Triangular fixed frame; 110. Left lifting cylinder; 111. Angular displacement sensor; 112. First stroke sensor; 113. Attached implement; 114. Second stroke sensor; 115. Agricultural machinery; 1. Oil tank; 2. Single piston rod hydraulic cylinder; 3. Relief safety valve; 4. Lifting circuit flow compensation valve; 5. Lifting circuit A chamber overload protection relief valve; 6. First plug; 7. Lifting circuit B chamber overload protection relief valve; 8. Second plug; 9. Left lateral circuit flow compensation valve; 10. Left lateral circuit control main valve; 11. Left lateral circuit A chamber overload protection relief valve; 12. Third plug; 13. Left lateral circuit B chamber overload protection relief valve; 14. Fourth plug; 15. Right lateral circuit... 16. Right-side lateral circuit control main valve; 17. Right-side lateral circuit A chamber overload protection relief valve; 18. Fifth plug; 19. Right-side lateral circuit B chamber overload protection relief valve; 20. Sixth plug; 21. Pull-up circuit flow compensation valve; 22. Pull-up circuit control main valve; 23. Pull-up circuit A chamber overload protection relief valve; 24. Seventh plug; 25. Pull-up circuit B chamber overload protection relief valve; 26. Eighth plug; 27. Relief pressure regulating valve; 28. Relief pressure regulating valve; 29. ​​Over Filter; 30. Electro-hydraulic proportional throttling compensation valve (8PT); 31. Electro-hydraulic proportional throttling compensation valve (7PT); 32. Pull-up circuit one-way throttling valve; 33. Electro-hydraulic proportional throttling compensation valve (6PT); 34. Electro-hydraulic proportional throttling compensation valve (5PT); 35. Right side circuit one-way throttling valve; 36. Electro-hydraulic proportional throttling compensation valve (4PT); 37. Electro-hydraulic proportional throttling compensation valve (3PT); 38. Left side circuit one-way throttling valve; 39. Electro-hydraulic proportional throttling compensation valve (2PT); 4 0. Electro-hydraulic proportional throttle compensation valve (1PT); 41. Lifting circuit control main valve; 42. Lifting circuit one-way throttle valve; 43. First one-way pressure compensation valve; 44. Second one-way pressure compensation valve; 45. Throttle valve; 46. Variable pump; 47. Engine; 48. Spring return hydraulic cylinder; 49. Central pull-up circuit rod hydraulic cylinder; 50. Right side lateral circuit hydraulic cylinder; 51. Left side lateral circuit hydraulic cylinder; 52. Right lifting circuit hydraulic cylinder; 53. Left lifting circuit hydraulic cylinder; Detailed Implementation To more clearly illustrate the technical solutions of the embodiments in this specification, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this specification. For those skilled in the art, these drawings can be applied to other similar scenarios without creative effort. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0012] Generally speaking, the terms "comprising" and "including" only indicate that the steps and elements are explicitly identified, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

[0013] Example 1 This invention uses angular displacement sensors and stroke sensors to collect three types of attitude data in real time: three-point suspension lifting height, implement lateral tilt, and front and rear pitch angles. The whole machine ECU receives the attitude detection signals and compares them with preset working attitude thresholds, calculates the attitude deviation, and outputs multiple electro-hydraulic proportional control signals. The control signals are input to the main control valves of each system to drive the corresponding lifting cylinder, lateral leveling cylinder, and upper lever cylinder to complete attitude correction. Each cylinder in the hydraulic circuit is independently equipped with an overload protection branch. By combining the layered vehicle electronic control architecture with the graded pressure hydraulic actuation circuit, the implement can be simultaneously lifted up and down, leveled left and right, and pitched forward and backward, continuously maintaining the preset working attitude of the implement when working in undulating farmland, improving tillage uniformity and operational stability.

[0014] like Figure 1 , Figure 3 As shown, a hydraulic attitude adjustment control system for a three-point suspension device includes a lifting cylinder, a lifting arm, a lower lever, a lateral leveling cylinder, a central upper lever cylinder, a triangular fixing frame, an angular displacement sensor, a stroke sensor, and a vehicle ECU. One end of the lifting cylinder is hinged to the lower lever, and the other end is hinged to the lifting arm. The other end of the lifting arm is connected to the agricultural machinery. One end of the lateral leveling cylinder is hinged to the lower lever. One end of the central upper lever cylinder is hinged to the upper part of the triangular fixing frame, and the other end is connected to the attachment point of the work implement. The angular displacement sensor is installed at the hinge shaft of the lifting arm, and the stroke sensor is installed at the end of the central upper lever cylinder and at the single-sided lateral cylinder. The angular displacement sensor and the stroke sensor are respectively connected to the vehicle ECU.

[0015] The lifting cylinder is hinged to the lower lever and the lifting arm, which in turn connects to the agricultural machinery, forming the execution link for lifting and lowering the implement. The lateral leveling cylinder is hinged to the lower lever and applies different pulling forces to the left and right sides of the implement. The central upper lever cylinder is hinged to the upper part of the triangular fixed frame 109 and the attachment point of the implement, adjusting the pitch angle of the implement by changing its length. An angular displacement sensor 111 is installed at the hinge shaft of the lifting arm to detect the rotation angle of the arm. Stroke sensors are installed at the end of the central upper lever cylinder 106 and at the single-sided lateral cylinder to detect the extension and retraction displacement of the cylinder piston rod. Each sensor transmits the detection signals to the vehicle ECU, which processes the data and makes control decisions. The lifting cylinder, lateral leveling cylinder, and central upper lever cylinder correspond to three independent degrees of freedom: lifting, lateral leveling, and pitch adjustment. These three functions do not interfere with each other, providing a mechanical basis for achieving multi-dimensional synchronous attitude adjustment. The arrangement of the angular displacement sensor 111 and the stroke sensor enables the system to acquire the machine's attitude information in real time, providing a data source for subsequent closed-loop control.

[0016] In a three-point suspension mechanism, the lifting actions on both the left and right sides must be synchronized; otherwise, the machine will tilt laterally. The lifting cylinders include a left lifting cylinder and a right lifting cylinder; the lifting arms include a left lifting arm and a right lifting arm; and the pull rods include a left pull rod and a right pull rod. One end of the left lifting cylinder is hinged to the left pull rod, and the other end is hinged to the left lifting arm. One end of the right lifting cylinder is hinged to the right pull rod, and the other end is hinged to the right lifting arm. The left and right lifting cylinders extend and retract synchronously, causing the left and right lifting arms to swing synchronously, which in turn drives the left and right pull rods to rise and fall synchronously.

[0017] The left lifting cylinder 110 is hinged to the left lower pull rod 102 and the left lifting swing arm 108, while the right lifting cylinder 105 is hinged to the right lower pull rod 103 and the right lifting swing arm 107. When the left and right lifting cylinders extend and retract synchronously, the lifting swing arms on both sides swing synchronously, and the lower pull rods rise and fall synchronously, thereby driving the entire machine to lift or lower. This symmetrical arrangement and synchronous drive structure ensures that the lifting height on both sides is consistent, avoiding machine tilting caused by asynchronous movement on one side.

[0018] In undulating farmland operations, the left and right drive wheels of a tractor may not be on the same plane, causing the implements to tilt laterally. The lateral leveling cylinders include a left lateral leveling cylinder and a right lateral leveling cylinder, and the pull rods include a left pull rod and a right pull rod. One end of the left lateral leveling cylinder is hinged to the left pull rod, and one end of the right lateral leveling cylinder is hinged to the right pull rod. The left lateral leveling cylinder extends and retracts independently to pull the left pull rod, and the right lateral leveling cylinder extends and retracts independently to pull the right pull rod, thus changing the height difference between the left and right pull rods.

[0019] The left-side lateral leveling cylinder 101 and the right-side lateral leveling cylinder 104 are hinged to the left lower lever 102 and the right lower lever 103, respectively. Unlike the synchronous extension and retraction of the lifting cylinder, the two lateral leveling cylinders can extend and retract independently. When the left-side lateral leveling cylinder 101 extends or retracts independently, the left lower lever 102 can be pulled to change its height, while the right lower lever 103 remains stationary, thereby changing the height difference between the left and right lower levers and achieving lateral leveling of the machine. This independent left-right drive structure decouples lateral leveling from lifting actions, and the leveling process does not affect the overall height of the machine.

[0020] The control system also includes a variable displacement pump, an engine, a spring-return hydraulic cylinder, a single-piston rod hydraulic cylinder, a relief safety valve, a control main valve, a flow compensation valve, a one-way throttle valve, an electro-hydraulic proportional throttle compensation valve, a one-way pressure compensation valve, a throttle valve, an oil tank, and an overload protection relief valve. The engine drives the variable displacement pump to draw hydraulic oil from the oil tank. The outlet of the variable displacement pump is connected to the one-way pressure compensation valve. The one-way pressure compensation valve works with the throttle valve to stabilize the main oil circuit supply pressure. The relief safety valve is located on the main oil circuit. The main oil circuit is connected to each control main valve. The solenoid coil of each control main valve receives the PWM control signal sent by the vehicle ECU. Each control main valve is connected to the corresponding flow compensation valve, one-way throttle valve, and overload protection relief valve. Each control main valve is also connected to the corresponding hydraulic cylinder.

[0021] like Figure 2The diagram shown is a hydraulic schematic, including: 1. Oil tank; 2. Single-piston rod hydraulic cylinder; 3. Relief safety valve; 4. Lifting circuit flow compensation valve; 5. Lifting circuit A chamber overload protection relief valve; 6. First plug; 7. Lifting circuit B chamber overload protection relief valve; 8. Left lateral circuit flow compensation valve; 9. Left lateral circuit control main valve; 10. Left lateral circuit A chamber overload protection relief valve; 11. Third plug; 12. Left lateral circuit B chamber overload protection relief valve; 13. Fourth plug; 14. 15. Right-side lateral loop flow compensation valve; 16. Right-side lateral loop control main valve; 17. Right-side lateral loop A chamber overload protection relief valve; 18. Fifth plug; 19. Right-side lateral loop B chamber overload protection relief valve; 20. Sixth plug; 21. Pull-up loop flow compensation valve; 22. Pull-up loop control main valve; 23. Pull-up loop A chamber overload protection relief valve; 24. Seventh plug; 25. Pull-up loop B chamber overload protection relief valve; 26. Eighth plug; 27. Relief pressure regulating valve; 28. Relief pressure regulating valve. 29. Filter; 30. Electro-hydraulic proportional throttling compensation valve (8PT); 31. Electro-hydraulic proportional throttling compensation valve (7PT); 32. Pull-up circuit one-way throttling valve; 33. Electro-hydraulic proportional throttling compensation valve (6PT); 34. Electro-hydraulic proportional throttling compensation valve (5PT); 35. Right side circuit one-way throttling valve; 36. Electro-hydraulic proportional throttling compensation valve (4PT); 37. Electro-hydraulic proportional throttling compensation valve (3PT); 38. Left side circuit one-way throttling valve; 39. Electro-hydraulic proportional throttling compensation valve (2PT). 39. Electro-hydraulic proportional throttle compensation valve (1PT) 40. Lifting circuit control main valve 41. Lifting circuit one-way throttle valve 42. First one-way pressure compensation valve 43. Second one-way pressure compensation valve 44. Throttle valve 45. Variable pump 46. Engine 47. Spring return type hydraulic cylinder 48. Central pull-up circuit rod hydraulic cylinder 49. Right side lateral circuit hydraulic cylinder 50. Left side lateral circuit hydraulic cylinder 51. Right side lifting circuit hydraulic cylinder 52. Left side lifting circuit hydraulic cylinder 53.

[0022] Engine 47 drives variable pump 46 to draw hydraulic oil from oil tank 1. The outlet of variable pump 46 is connected to a first one-way pressure compensation valve 43 and a second one-way pressure compensation valve 44. The two one-way pressure compensation valves, together with throttle valve 45, stabilize the oil supply pressure of the main oil circuit and prevent pressure fluctuations from affecting control accuracy. Single piston rod hydraulic cylinder 2 and spring return hydraulic cylinder 48 drive the swashplate of variable pump 46 to deflect by changing their own stroke angle, thereby adjusting the flow rate and direction of the pump output oil. Overflow safety valve 3 is installed on the main oil circuit, limiting the maximum working pressure of the entire circuit to 20MPa. When the system is overloaded, the oil overflows back to oil tank 1. The main hydraulic circuit is connected to the lifting circuit control main valve 41, the left lateral circuit control main valve 10, the right lateral circuit control main valve 16, and the pull-up circuit control main valve 22. Each control main valve's solenoid coil receives a PWM control signal from the vehicle ECU, generating electromagnetic thrust to move the directional valve spool, changing the on / off direction of the hydraulic circuit and the hydraulic flow rate, thereby driving the corresponding hydraulic cylinder's extension and retraction. Each control main valve is connected to a corresponding flow compensation valve, a one-way throttle valve, and an overload protection relief valve. The flow compensation valve is used for pressure and flow stabilization, while the one-way throttle valve controls the cylinder's movement speed through throttling damping, ensuring smooth and shock-free movement. Each hydraulic cylinder has an overload protection relief valve in both chambers, automatically overflowing to relieve pressure when the lifting load suddenly increases or the pressure exceeds the limit, protecting the cylinder and hydraulic circuit. The variable displacement pump 46's displacement adjustment, the control main valve's directional control, and the throttling speed regulation work together to enable the system to output appropriate hydraulic power according to ECU commands, achieving stepless speed regulation of the cylinder's movement.

[0023] Since the system includes four independent execution circuits: lifting, left lateral leveling, right lateral leveling, and upper lever pitch, the control main valve and overload protection for each circuit need to be configured separately.

[0024] The control main valve includes a lifting circuit control main valve, a left lateral circuit control main valve, a right lateral circuit control main valve, and an upward circuit control main valve. The overload protection relief valve includes an overload protection relief valve for lifting circuit A chamber, an overload protection relief valve for lifting circuit B chamber, an overload protection relief valve for left lateral circuit A chamber, an overload protection relief valve for left lateral circuit B chamber, an overload protection relief valve for right lateral circuit A chamber, an overload protection relief valve for right lateral circuit B chamber, an overload protection relief valve for upward circuit A chamber, and an overload protection relief valve for upward circuit B chamber. Each hydraulic cylinder has two chambers independently equipped with corresponding overload protection relief valves.

[0025] This claim defines four main control valves corresponding to the lifting circuit, the left lateral circuit, the right lateral circuit, and the pull-up circuit, respectively. Each hydraulic cylinder in each circuit has chamber A and chamber B, and each chamber is independently equipped with an overload protection relief valve. For example, in the lifting circuit, the overload protection relief valve 5 for chamber A and the overload protection relief valve 7 for chamber B monitor the oil pressure in the two chambers of the lifting cylinder, respectively. This independent configuration ensures that in the event of a single-circuit overload, only that circuit overflows and releases pressure, without affecting the normal operation of other circuits, thus solving the problem in the prior art where large lateral forces easily damage the suspension rods.

[0026] The lifting circuit is the most basic and frequently used function in the suspension system, and its reversing control is achieved through an electro-hydraulic proportional throttle compensation valve.

[0027] The electro-hydraulic proportional throttling compensation valve includes a first electro-hydraulic proportional throttling compensation valve and a second electro-hydraulic proportional throttling compensation valve. The lifting circuit controls the main valve to switch to the left position, right position, or middle position by being energized through the first electro-hydraulic proportional throttling compensation valve and the second electro-hydraulic proportional throttling compensation valve.

[0028] When the first electro-hydraulic proportional throttling compensation valve 40 and the second electro-hydraulic proportional throttling compensation valve 39 are energized, the valve core of the drive lifting circuit control main valve 41 switches to the left, right, or center position. When the first electro-hydraulic proportional throttling compensation valve 40 is energized, the valve core switches to the left position, and high-pressure oil enters the rod chambers of the right lifting circuit hydraulic cylinder 52 and the left lifting circuit hydraulic cylinder 53. The piston rod retracts synchronously, driving the lifting cylinder to raise the implement. When the second electro-hydraulic proportional throttling compensation valve 39 is energized, the valve core switches to the right position, and high-pressure oil flows in the reverse direction into the rodless chamber of the cylinder. The piston rod extends synchronously, and the implement descends. When both proportional valves are de-energized, the valve core is in the center position, the oil circuit is closed, and the cylinder remains stationary. By adjusting the duty cycle of the PWM signal, the opening degree of the proportional valve can be controlled, thereby adjusting the flow rate of oil entering the cylinder and achieving stepless adjustment of the lifting speed. The lifting circuit flow compensation valve 4 and the lifting circuit one-way throttle valve 42 respectively play the roles of stabilizing pressure and flow and throttling damping. The three work together to make the lifting action smooth and without impact.

[0029] An angular displacement sensor collects the analog voltage signal generated by the rotation of the lifting arm and transmits it to the lifting control ECU. The lifting control ECU converts the arm rotation angle into the actual height of the attached implement above the ground. The stroke sensors include a first stroke sensor and a second stroke sensor. The first stroke sensor is installed at the end of the central upper pull rod cylinder, collects the voltage signal corresponding to the extension and retraction displacement of the piston rod of the central upper pull rod cylinder, and transmits it to the pitch control ECU. The pitch control ECU converts the cylinder extension and retraction stroke into the current pitch angle of the implement in the soil. The second stroke sensor is installed at the lateral cylinder on one side, collects the extension and retraction displacement signal of the lateral cylinder on one side, and sends it to the swing control ECU. The swing control ECU retrieves the stroke data of the left and right lateral cylinders, performs difference calculations, and calculates the current left and right lateral tilt deviation of the implement.

[0030] An angular displacement sensor 111 is installed at the hinge shaft of the lifting arm, collecting the analog voltage signal generated by the rotation of the arm. The amplitude of this signal changes linearly with the swing angle of the arm. The sensor transmits the continuous angular analog quantity to the lifting control ECU in real time. The ECU retrieves the geometric parameters of the suspension mechanism and converts the arm rotation angle into the current actual height of the attached implement 113 above the ground using a trigonometric function conversion formula. A first stroke sensor 112 is installed at the end of the central upper pull rod cylinder 106, collecting the voltage signal corresponding to the extension and retraction displacement of the cylinder piston rod and transmitting it to the pitch control ECU. The ECU converts the extension and retraction stroke of the cylinder into the current pitch angle of the implement when it is inserted into the soil, based on the geometric relationship between the upper pull rod and the implement hinge mechanism. A second stroke sensor 114 is installed at the single-sided lateral cylinder, collecting the extension and retraction displacement signal of that side cylinder and sending it to the swing control ECU. The ECU simultaneously retrieves the stroke data of the left and right lateral cylinders, performs difference calculations, and directly calculates the current left and right lateral tilt deviation of the implement. The three ECUs process three different attitude data independently without interfering with each other, and each calls its corresponding geometric conversion model, ensuring the real-time performance and accuracy of attitude detection.

[0031] This control system uses angular displacement sensors and stroke sensors to collect real-time attitude data on three types: lifting height of the three-point suspension, lateral tilt of the implement, and pitch angle. The machine's ECU receives attitude detection signals and compares them with preset working attitude thresholds, calculates the attitude deviation, and outputs multiple electro-hydraulic proportional control signals. These control signals are input to the main control valves of each system, driving the corresponding lifting cylinders, lateral leveling cylinders, and upper tie rod cylinders to complete attitude correction. Each cylinder in the hydraulic circuit is independently equipped with an overload protection branch. By combining a layered vehicle electronic control architecture with a graded pressure hydraulic actuation circuit, the system can simultaneously achieve implement lifting up and down, lateral leveling, and pitch angle adjustment, continuously maintaining the preset working attitude of the implement when operating in undulating farmland, improving tillage uniformity and operational stability. This solves the technical problems of existing three-point suspension systems, such as single attitude adjustment, inability to simultaneously achieve multi-dimensional attitude closed-loop control, and easy damage to suspension components due to large lateral forces.

[0032] Example 2 This embodiment provides a hydraulic attitude adjustment control method for a three-point suspension device, such as... Figure 4 As shown, it includes the following steps: Pre-calibrate the working posture reference value, calibrate the instantaneous reading of the detection values ​​of the angular displacement sensor and the stroke sensor, convert them into the corresponding ground clearance, left and right tilt amount and pitch angle reference values ​​and store them; During field operations, three attitude data are collected simultaneously. The rotation angle of the lifting arm is collected by the angular displacement sensor and converted into the actual height of the implement above the ground. The extension and retraction displacement of the upper tie rod cylinder is collected by the stroke sensor installed at the end of the central upper tie rod cylinder and converted into the current pitch angle of the implement. The extension and retraction displacement of the lateral cylinder is collected by the stroke sensor installed at the lateral cylinder on one side and combined with the stroke data of the other side cylinder to perform difference calculation and calculate the current left and right lateral tilt deviation of the implement. The real-time calculated altitude data, left and right lateral tilt deviation data, and front and rear pitch angle data are compared with the pre-stored calibration reference attitude values ​​to determine the direction and magnitude of the deviation. When the real-time attitude deviates from the reference threshold range, a PWM proportional electronic control signal with a corresponding duty cycle is generated and sent to the solenoid coil of each control main valve to control the extension and retraction of the corresponding hydraulic cylinder to complete the attitude correction.

[0033] Before operation, the operator adjusts the attached implement 113 to the standard tillage height, standard horizontal posture, and standard soil penetration angle, completing a one-time benchmark calibration. At the moment of calibration, the vehicle's ECU simultaneously reads the raw detection values ​​from the angular displacement sensor 111 and the stroke sensor. Using a built-in geometric conversion model, the raw electrical signals from the sensors are converted into corresponding ground clearance, left and right tilt, and pitch angle benchmark values, which are then permanently stored in the vehicle's ECU's internal storage module. Subsequent field operations do not require manual re-entry of the target posture parameters.

[0034] Angular displacement sensor 111 collects the rotation angle of the lifting arm in real time and converts it into the actual height of the implement above the ground. First stroke sensor 112 collects the extension and retraction displacement of the central upper pull rod cylinder 106 and converts it into the pitch angle. Second stroke sensor 114 collects the extension and retraction displacement of the lateral cylinder on one side and performs a difference calculation with the stroke data of the other lateral cylinder to calculate the left and right lateral tilt deviation. The three attitude data are collected synchronously without lag.

[0035] The real-time attitude data is compared with the calibration benchmark value to determine the direction and magnitude of the deviation. When the real-time attitude deviates from the benchmark threshold range, the ECU autonomously generates a PWM proportional control signal with a corresponding duty cycle, without the need for manual adjustment commands. The fourth step is to send the PWM control signal to the solenoid coils of each control valve, driving the corresponding hydraulic cylinders to automatically extend and retract, thus completing the autonomous correction of the machine's attitude.

[0036] This method connects calibration, data acquisition, computation, and control into a complete closed-loop control chain, achieving a fully automated process from attitude detection to correction execution. The calibration step solves the problem of attitude parameter differences after installation of different implements, making the system universal. Simultaneous acquisition of three-channel attitude data ensures comprehensive perception of the implement's spatial attitude. The ECU automatically calculates the deviation and generates control signals without manual intervention. The hydraulic actuator responds to the electrical signals to complete the correction, forming a complete sensing-computation-execution closed loop.

[0037] In the step of pre-calibrating the reference values ​​of the working posture, after adjusting the attached agricultural implements to the standard tillage height, standard horizontal posture and standard soil entry pitch angle, a one-time reference calibration is completed. At the moment of calibration, the original detection values ​​of the angular displacement sensor and all stroke sensors are read simultaneously. The original electrical signals are converted into the corresponding reference values ​​of ground clearance, left and right tilt and pitch angle through the geometric conversion model and stored in the internal storage module of the vehicle ECU.

[0038] Before operation, the operator adjusts the attached implement 113 to the standard tillage height, standard horizontal posture, and standard soil penetration angle, completing a one-time benchmark calibration. At the moment of calibration, the vehicle ECU simultaneously reads the raw detection values ​​from the angular displacement sensor 111, the first stroke sensor 112, and the second stroke sensor 114. Using a geometric conversion model, the raw electrical signals are converted into corresponding ground clearance, left and right tilt, and pitch angle benchmark values, which are then stored in the vehicle ECU's internal storage module. This single calibration allows for permanent use, eliminating the need for manual input of posture target parameters during subsequent field operations, thus solving the problem of manually setting posture parameters before each operation in traditional systems.

[0039] In the posture correction process, when the lifting circuit needs to raise the implement, the first electro-hydraulic proportional throttling compensation valve is energized, causing the lifting circuit control main valve core to switch to the left position. High-pressure oil enters the rod chambers of the right and left lifting circuit hydraulic cylinders, and the piston rods retract synchronously, driving the lifting cylinder to raise the implement. When the lifting circuit needs to lower the implement, the second electro-hydraulic proportional throttling compensation valve is energized, causing the lifting circuit control main valve core to switch to the right position. High-pressure oil enters the rodless chamber of the cylinder, and the piston rods extend synchronously, lowering the implement. When the stroke reaches the target reference value, the power supply to all proportional valves is cut off, the valve cores are in the neutral position, the oil circuit is closed, and the cylinder remains stationary.

[0040] When the first electro-hydraulic proportional throttle compensation valve 40 is energized, the valve core of the lifting circuit control main valve 41 switches to the left position. High-pressure oil enters the rod chambers of the right lifting circuit hydraulic cylinder 52 and the left lifting circuit hydraulic cylinder 53. The piston rods of both chambers retract synchronously, driving the left lifting cylinder 110 and the right lifting cylinder 105 to lift the implement synchronously. When the second electro-hydraulic proportional throttle compensation valve 39 is energized, the valve core switches to the right position. High-pressure oil flows in the reverse direction into the rodless chamber of the cylinder. The piston rod extends synchronously, and the implement descends smoothly. When the stroke reaches the target reference value, the ECU cuts off the power supply to all proportional valves, the valve core is in the neutral position, the oil circuit is closed, the cylinder remains stationary, and the implement's height above the ground remains unchanged. The lifting circuit flow compensation valve 4 and the lifting circuit one-way throttle valve 42 respectively play the roles of pressure stabilization and damping, ensuring a smooth and shock-free lifting process.

[0041] The attitude correction process covers three operating conditions: elevation correction, lateral leveling correction, and pitch correction. During lateral leveling correction, the left lateral circuit control main valve 10 and the right lateral circuit control main valve 16 switch positions under the energization of their respective electro-hydraulic proportional throttle compensation valves (3PT), (4PT), (5PT), and (6PT), respectively, pushing the left lateral circuit hydraulic cylinder 51 and the right lateral circuit hydraulic cylinder 50 to extend and retract, achieving lateral leveling. During pitch correction, the pull-up circuit control main valve 22 switches positions under the energization of the electro-hydraulic proportional throttle compensation valves (7PT) and (8PT), pushing the central pull-up circuit rod hydraulic cylinder 49 to extend and retract, achieving forward and backward pitch adjustment. Each circuit operates independently and does not interfere with the others.

[0042] The specific work process is as follows: Before operation, the operator adjusts the attached implement 113 to the standard tillage height, standard horizontal posture, and standard soil penetration angle, completing a one-time benchmark calibration. At the moment of calibration, the whole machine ECU simultaneously reads the original detection values ​​of the angular displacement sensor 111, the stroke sensor, and the stroke sensor. Through the built-in geometric conversion model, the original electrical signals of the sensors are converted into corresponding reference values ​​for ground clearance, left and right tilt, and pitch angle, which are permanently stored in the internal storage module of the whole machine ECU. Subsequent field operations do not require manual re-entry of the posture target parameters.

[0043] During field operations, three-way attitude data acquisition is carried out simultaneously: Angular displacement sensor 111, installed at the hinge shaft of the lifting arm, collects the analog voltage signal generated by the rotation of the arm in real time. The signal amplitude changes linearly with the swing angle of the arm. The sensor transmits the continuous angular analog quantity to the lifting control ECU in real time. The ECU retrieves the geometric dimension parameters of the suspension mechanism and converts the arm rotation angle into the actual height of the attached implement 113 above the ground in real time using trigonometric function conversion formulas. The stroke sensor installed at the end of the central upper pull rod cylinder 106 collects the voltage signal corresponding to the extension and retraction displacement of the cylinder piston rod in real time. The signal is transmitted to the swing control ECU. The ECU converts the extension and retraction stroke of the cylinder into the current pitch angle of the implement in the soil based on the geometric relationship between the upper pull rod and the hinge mechanism of the implement. The stroke sensor 8, installed on the lower pull rod, collects the extension and retraction displacement signal of the lateral cylinder on one side in real time and sends it to the swing control ECU. The ECU simultaneously retrieves the stroke data of the lateral cylinders on the left and right sides, performs difference calculations, and directly calculates the current left and right lateral tilt deviation of the implement.

[0044] The lift control ECU, sway control ECU, and pitch control ECU continuously calculate the difference between the real-time height, tilt angle, and pitch deviation data and the pre-stored calibration reference attitude values, automatically determining the direction and magnitude of the deviation. When the real-time attitude deviates from the reference threshold range, the ECU autonomously generates a PWM proportional electronic control signal with the corresponding duty cycle, without requiring manual adjustment commands. The whole machine ECU sends the PWM control signal to the solenoid coils of the control main valves of each system in the hydraulic circuit through the vehicle's CAN bus. After receiving the electrical signal, the solenoid coil generates electromagnetic thrust to push the valve core of the directional valve to move, changing the opening and closing direction of the hydraulic oil circuit and the oil flow rate, thereby driving the corresponding hydraulic cylinder to automatically extend and retract, completing the autonomous correction of the implement's attitude. At the same time, the engine ECU, transmission system ECU, and steering control ECU synchronize the agricultural machinery 115's travel and power condition data to the whole machine ECU in real time. Information on conditions such as travel bumps and sudden load changes participates in the attitude compensation calculation, optimizing the correction response speed and ensuring continuous and stable operation of attitude adjustment on undulating terrain.

[0045] Engine 47 drives variable pump 46 to output hydraulic oil; single-piston rod hydraulic cylinder 2 and spring-return hydraulic cylinder 48 drive variable pump 46 to deflect the swashplate angle through their own stroke changes, thereby adjusting the flow rate and direction of the pump output oil; the pump outlet is connected in parallel with first one-way pressure compensation valve 43 and second one-way pressure compensation valve 44, which work with throttle valve 45 to stabilize the main oil circuit supply pressure; overflow safety valve 3 is the system's main overflow valve, located in the main oil circuit, limiting the maximum working pressure of the entire circuit to 20MPa, and the oil overflows back to oil tank 1 when the system is overloaded. The electronic control system sends PWM electrical signals to the solenoid coils of the main control valves of each system. The coils are energized and drive the valve core to switch, and the high-pressure oil in the main oil circuit enters the corresponding execution branch, driving the cylinder to complete the attitude correction.

[0046] The lifting and adjustment process of the machine: The angular displacement sensor 111 collects the actual stroke height of the hydraulic cylinder in real time and feeds it back to the electronic control. The electronic control compares the real-time height with the preset calibration benchmark and calculates the stroke difference. When there is a height deviation, the corresponding current is output to the proportional valve. According to the energizing conditions of the electro-hydraulic proportional throttling compensation valve (1PT) 40 and the electro-hydraulic proportional throttling compensation valve (2PT) 39, the valve core of the lifting control main valve is driven to switch to the left, right, or middle position. When the electro-hydraulic proportional throttling compensation valve (1PT) 40 is energized, the valve core switches to the left position, and high-pressure oil enters the rod chamber of the hydraulic cylinder of the right lifting circuit and the hydraulic cylinder of the left lifting circuit. The piston rod retracts synchronously, driving the left and right lifting cylinders to lift the implement. When the electro-hydraulic proportional throttling compensation valve (2PT) 39 is energized, the valve core switches to the right position, and high-pressure oil flows in reverse into the rodless chamber of the cylinder. The piston rod extends synchronously, and the implement descends smoothly. When the stroke reaches the target reference value, the electronic control cuts off the power supply to all proportional valves, the valve core is in the middle position, the oil circuit is closed, the cylinder remains stationary, and the height of the implement off the ground remains unchanged.

[0047] The hydraulic fluid first passes through the flow compensation valve of the lifting system to stabilize the pressure and flow, and then flows through the one-way throttle valve 45 of the lifting system. The lifting speed is controlled by the throttle damping to ensure smooth and shock-free operation. The overload protection overflow valves of the lifting system A chamber and B chamber monitor the hydraulic pressure of the two chambers of the lifting cylinder in real time. When the lifting load suddenly increases or the pressure exceeds the standard, the valve automatically overflows to release pressure, protecting the cylinder and oil circuit and preventing the implement from falling due to its own weight.

[0048] Similarly, the main control valves of each circuit switch their working positions according to the energization status, thereby driving the hydraulic cylinders of each circuit to extend and retract, realizing the movement of mechanical parts, and achieving the lifting and lowering, horizontal leveling, and pitching and tilting of agricultural implements.

[0049] In summary, the present invention has the following advantages: 1. The mechanical structure achieves three-degree-of-freedom decoupled adjustment. Lifting, lateral leveling, and pitching depth are driven by independent hydraulic cylinders, and each posture adjustment does not interfere with the others. It can adapt to complex terrains such as slopes and paddy fields, and the posture adjustment of agricultural implements is more comprehensive.

[0050] 2. Each branch is equipped with a composite speed regulation structure consisting of a flow compensation valve and a multi-stage electro-hydraulic proportional throttling compensation valve. The energized state of the electronically controlled proportional valve switches the working position of the main valve, achieving stepless and stable speed regulation of the cylinder action and smooth and shock-free adjustment of the agricultural implement posture.

[0051] 3. The electronic control system relies on angular displacement and stroke sensors to collect real-time attitude data of agricultural implements, pre-calibrate the reference height and pitch angle, automatically calculate tilt and tillage depth deviations, and output corresponding proportional electrical signals to drive hydraulic branch correction, realizing fully automatic closed-loop attitude correction under farmland undulation conditions without the need for manual adjustment.

[0052] 4. The electronic control unit integrates multi-way valve proportional throttling, branch pressure classification, and overload safety protection. Hydraulic actuation, sensor detection, and electronic control algorithm are linked and matched. The entire three-point suspension attitude adjustment system has a high degree of integration, fast response speed, and is suitable for various operating scenarios such as paddy fields and dry land.

[0053] 5. The electromechanical-hydraulic integrated closed-loop control system integrates the electrical control with unified control of attitude adjustment, pump displacement matching, graded pressure regulation and overload protection logic. The sensing, calculation and hydraulic execution are deeply linked, resulting in fast system response and balancing operational accuracy, structural reliability and overall energy consumption optimization.

[0054] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A hydraulic attitude adjustment control system for a three-point suspension device, characterized in that, This includes lifting cylinders, lifting swing arms, pull rods, lateral leveling cylinders, central upper pull rod cylinders, triangular fixing frames, angular displacement sensors, stroke sensors, and the vehicle ECU; One end of the lifting cylinder is hinged to a pull rod, and the other end is hinged to a lifting swing arm. The other end of the lifting swing arm is connected to the agricultural machinery. One end of the lateral leveling cylinder is hinged to a pull rod. One end of the central upper pull rod cylinder is hinged to the upper part of the triangular fixed frame, and the other end is connected to the attachment point of the working implement. The angular displacement sensor is installed at the hinge shaft of the lifting swing arm, and the stroke sensor is installed at the end of the central upper pull rod cylinder and the single-sided lateral cylinder. The angular displacement sensor and the stroke sensor are respectively connected to the vehicle ECU.

2. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 1, characterized in that, The lifting cylinder includes a left lifting cylinder and a right lifting cylinder; the lifting swing arm includes a left lifting swing arm and a right lifting swing arm; the pull rod includes a left pull rod and a right pull rod. One end of the left lifting cylinder is hinged to the left pull rod, and the other end is hinged to the left lifting swing arm. One end of the right lifting cylinder is hinged to the right pull rod, and the other end is hinged to the right lifting swing arm. The left and right lifting cylinders extend and retract synchronously, causing the left and right lifting swing arms to swing synchronously, and driving the left and right pull rods to rise and fall synchronously.

3. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 1, characterized in that, The lateral leveling cylinder includes a left lateral leveling cylinder and a right lateral leveling cylinder. The pull rod includes a left pull rod and a right pull rod. One end of the left lateral leveling cylinder is hinged to the left pull rod, and one end of the right lateral leveling cylinder is hinged to the right pull rod. The left lateral leveling cylinder extends and retracts independently to pull the left pull rod, and the right lateral leveling cylinder extends and retracts independently to pull the right pull rod, thereby changing the height difference between the left and right pull rods.

4. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 1, characterized in that, It also includes a variable displacement pump, an engine, a spring-return hydraulic cylinder, a single-piston rod hydraulic cylinder, a relief safety valve, a control main valve, a flow compensation valve, a one-way throttle valve, an electro-hydraulic proportional throttle compensation valve, a one-way pressure compensation valve, a throttle valve, an oil tank, and an overload protection relief valve. The engine drives the variable displacement pump to draw hydraulic oil from the oil tank. The outlet of the variable displacement pump is connected to the one-way pressure compensation valve. The one-way pressure compensation valve works with the throttle valve to stabilize the main oil circuit supply pressure. The relief safety valve is located on the main oil circuit. The main oil circuit is connected to each control main valve. The solenoid coil of each control main valve receives the PWM control signal sent by the vehicle ECU. Each control main valve is connected to the corresponding flow compensation valve, one-way throttle valve, and overload protection relief valve. Each control main valve is also connected to the corresponding hydraulic cylinder.

5. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 4, characterized in that, The control main valve includes a lifting circuit control main valve, a left lateral circuit control main valve, a right lateral circuit control main valve, and an upward circuit control main valve. The overload protection relief valve includes an overload protection relief valve for lifting circuit A chamber, an overload protection relief valve for lifting circuit B chamber, an overload protection relief valve for left lateral circuit A chamber, an overload protection relief valve for left lateral circuit B chamber, an overload protection relief valve for right lateral circuit A chamber, an overload protection relief valve for right lateral circuit B chamber, an overload protection relief valve for upward circuit A chamber, and an overload protection relief valve for upward circuit B chamber. Each hydraulic cylinder has two chambers independently equipped with corresponding overload protection relief valves.

6. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 4, characterized in that, The electro-hydraulic proportional throttling compensation valve includes a first electro-hydraulic proportional throttling compensation valve and a second electro-hydraulic proportional throttling compensation valve. The lifting circuit controls the main valve to switch to the left position, right position, or middle position by being energized through the first electro-hydraulic proportional throttling compensation valve and the second electro-hydraulic proportional throttling compensation valve.

7. The hydraulic attitude adjustment control system for the three-point suspension device as described in claim 1, characterized in that, An angular displacement sensor collects the analog voltage signal generated by the rotation of the lifting arm and transmits it to the lifting control ECU. The lifting control ECU converts the arm rotation angle into the actual height of the attached implement above the ground. The stroke sensors include a first stroke sensor and a second stroke sensor. The first stroke sensor is installed at the end of the central upper pull rod cylinder, collects the voltage signal corresponding to the extension and retraction displacement of the piston rod of the central upper pull rod cylinder, and transmits it to the pitch control ECU. The pitch control ECU converts the cylinder extension and retraction stroke into the current pitch angle of the implement in the soil. The second stroke sensor is installed at the lateral cylinder on one side, collects the extension and retraction displacement signal of the lateral cylinder on one side, and sends it to the swing control ECU. The swing control ECU retrieves the stroke data of the left and right lateral cylinders, performs difference calculations, and calculates the current left and right lateral tilt deviation of the implement.

8. A hydraulic attitude adjustment control method for a three-point suspension device, characterized in that, Includes the following steps: Pre-calibrate the working posture reference value, calibrate the instantaneous reading of the detection values ​​of the angular displacement sensor and the stroke sensor, convert them into the corresponding ground clearance, left and right tilt amount and pitch angle reference values ​​and store them; During field operations, three attitude data are collected simultaneously. The rotation angle of the lifting arm is collected by the angular displacement sensor and converted into the actual height of the implement above the ground. The extension and retraction displacement of the upper tie rod cylinder is collected by the stroke sensor installed at the end of the central upper tie rod cylinder and converted into the current pitch angle of the implement. The extension and retraction displacement of the lateral cylinder is collected by the stroke sensor installed at the lateral cylinder on one side and combined with the stroke data of the other side cylinder to perform difference calculation and calculate the current left and right lateral tilt deviation of the implement. The real-time calculated altitude data, left and right lateral tilt deviation data, and front and rear pitch angle data are compared with the pre-stored calibration reference attitude values ​​to determine the direction and magnitude of the deviation. When the real-time attitude deviates from the reference threshold range, a PWM proportional electronic control signal with a corresponding duty cycle is generated and sent to the solenoid coil of each control main valve to control the extension and retraction of the corresponding hydraulic cylinder to complete the attitude correction.

9. The hydraulic attitude adjustment and control method for a three-point suspension device as described in claim 8, characterized in that, In the step of pre-calibrating the reference values ​​of the working posture, after adjusting the attached agricultural implements to the standard tillage height, standard horizontal posture and standard soil entry pitch angle, a one-time reference calibration is completed. At the moment of calibration, the original detection values ​​of the angular displacement sensor and all stroke sensors are read simultaneously. The original electrical signals are converted into the corresponding reference values ​​of ground clearance, left and right tilt and pitch angle through the geometric conversion model and stored in the internal storage module of the vehicle ECU.

10. The hydraulic attitude adjustment and control method for a three-point suspension device as described in claim 8, characterized in that, In the posture correction process, when the lifting circuit needs to raise the implement, the first electro-hydraulic proportional throttling compensation valve is energized, causing the lifting circuit control main valve core to switch to the left position. High-pressure oil enters the rod chambers of the right and left lifting circuit hydraulic cylinders, and the piston rods retract synchronously, driving the lifting cylinder to raise the implement. When the lifting circuit needs to lower the implement, the second electro-hydraulic proportional throttling compensation valve is energized, causing the lifting circuit control main valve core to switch to the right position. High-pressure oil enters the rodless chamber of the cylinder, and the piston rods extend synchronously, lowering the implement. When the stroke reaches the target reference value, the power supply to all proportional valves is cut off, the valve cores are in the neutral position, the oil circuit is closed, and the cylinder remains stationary.

Images