Lifting control system and method based on double tilt angle sensors

Abstract

The invention discloses a lifting control system and method based on double tilt angle sensors. The lifting control system comprises a three-point suspension system, a main controller and the double tilt angle sensors. Wherein the three-point suspension system is connected with a tractor body, and the three-point suspension system comprises a lower pull rod; wherein one tilt angle sensor is arranged on the lower pull rod and is used for measuring the tilt angle value of the lower pull rod; the other tilt angle sensor is arranged on the tractor body and is used for measuring the tilt angle value of the tractor body; the double-tilt-angle sensor is connected with the main controller through a CAN bus. According to the lifting control system, the relative angle data of the tractor body and the lower pull rod are collected in real time through the double tilt angle sensors, accurate control and real-time monitoring of the lifting process of agricultural tools are achieved, and a three-point suspension system can adapt to complex terrains.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery equipment, and in particular to a lifting control system and method based on a dual inclination sensor. Background Art

[0002] The use of agricultural implements can improve the level of agricultural mechanization and save labor. Existing agricultural implements are generally connected to the three-point hitch system of a tractor. The three-point hitch system mainly realizes the lifting of agricultural implements through a hydraulic lifting mechanism. Traditional three-point hitch systems mainly rely on manual operation or electro-hydraulic proportional valves for control. Electro-hydraulic proportional valves have the characteristics of high cost and complex maintenance. Therefore, for small hill tractors, conventional electromagnetic control multi-way hydraulic valves are generally used, which cannot accurately adjust the flow rate, resulting in low control accuracy of the lifting angle. Moreover, traditional three-point hitch systems usually adopt a single sensor control system, such as using a position sensor or a pressure sensor, to monitor the height or pressure change of the hydraulic lifting mechanism in real time. The single sensor control system still has the problem of low control accuracy, making the three-point hitch system less adaptable in complex terrains. Summary of the Invention

[0003] An object of the present invention is to overcome the above existing problems and provide a lifting control system based on a dual inclination sensor. This lifting control system can collect the relative angle data of the tractor body and the lower link in real time through the dual inclination sensor, realize the precise control and real-time monitoring of the lifting process of agricultural implements, and enable the three-point hitch system to adapt to complex terrains.

[0004] Another object of the present invention is to provide a lifting control method based on a dual inclination sensor.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] A lifting control system based on a dual inclination sensor includes a three-point hitch system, a main controller, and a dual inclination sensor; wherein, the three-point hitch system is connected to the tractor body, and the three-point hitch system includes a lower link; one of the inclination sensors is installed on the lower link and is used to measure the inclination angle value of the lower link; the other inclination sensor is installed on the tractor body and is used to measure the inclination angle value of the tractor body; the dual inclination sensor is connected to the main controller through a CAN bus.

[0007] The working principle of the above lifting control system based on a dual inclination sensor is:

[0008] The inclination angle value of the lower link and the inclination angle value of the tractor body are measured by a dual-inclination sensor. The relative angle data (the actual angle value of the three-point hitch system) of the tractor body and the lower link can be collected in real time through the two inclination angle values. Through the control of the main controller, precise control and real-time monitoring of the lifting process of the agricultural implement are realized.

[0009] A preferred embodiment of the present invention, wherein the lifting control system further includes a hydraulic cylinder, a relay, and a solenoid valve; the relay is connected to the main controller and the solenoid valve, and the solenoid valve is connected to the hydraulic cylinder. In the above structure, the main controller transmits a control signal to the relay, controls the solenoid valve to work through the relay, the solenoid valve opens, and under the drive of the hydraulic cylinder, the pull rod moves, realizing the lifting control of the three-point hitch system.

[0010] Preferably, the three-point hitch system further includes a lifting arm, an upper link, a lifting rod, and a column; wherein, one end of the lifting arm is hinged to the tractor body, and the other end is hinged to one end of the lifting rod; the other end of the lifting rod is hinged to the middle of the lower link; the hydraulic cylinder acts on the lifting arm; one end of the lower link is hinged to the tractor body, and the other end is hinged to one end of the column; one end of the upper link is hinged to the tractor body, and the other end is hinged to the other end of the column. In the above structure, the hydraulic cylinder drives the lifting arm to move, then pulls the lifting rod, driving the lower link to move, thereby completing the lifting and lowering actions of the agricultural implement.

[0011] Preferably, the lifting control system further includes a display screen, which is used to display in real time the actual angle value of the three-point hitch system, the inclination angle value of the tractor body, the target angle setting, the target angle value, the manual / automatic mode setting, and the dead zone setting; the actual angle value of the three-point hitch system is the absolute value of the value obtained by subtracting the inclination angle value of the tractor body from the inclination angle value of the lower link. By setting the display screen, various information can be displayed and operations and settings can be performed through the display screen, which is very convenient to use. The main controller obtains the inclination angle value of the lower link and the inclination angle value of the tractor body in real time, then obtains the actual angle value of the three-point hitch system through the two inclination angle values, calculates the difference between the actual angle value and the target angle value, judges according to the positive and negative of the difference to obtain a control signal, transmits the control signal to the relay, controls the solenoid valve to work through the relay, thereby controlling the movement of the lower link, realizing the lifting control of the three-point hitch system, and finally moving the three-point hitch system to the position corresponding to the target angle value.

[0012] Preferably, in the initial state, the three-point hitch system is in the raised state, and the three-point hitch system is located at the angle position of the upper limit angle; the specific steps of the manual mode are:

[0013] Select the manual mode on the display screen. Then, after entering the target angle value on the display screen, the main controller calculates the difference between the actual angle value and the target angle value to obtain a control signal. The control signal is transmitted to the relay, and the relay controls the solenoid valve to work. The hydraulic cylinder drives the lower pull rod to move, thereby controlling the three-point hitch system to perform a lowering action until the agricultural implement moves to the position corresponding to the target angle value.

[0014] Preferably, the specific steps of the automatic mode are as follows: Select the automatic mode on the display screen. The other steps of the automatic mode are the same as the specific steps of the manual mode. The difference is that after the agricultural implement moves to the position corresponding to the target angle value, when the tractor body tilts, the main controller automatically adjusts the target angle value according to the tilt angle value of the tractor body obtained in real time. The purpose is that when the tractor body tilts and the tillage depth of the agricultural implement changes, the position of the agricultural implement is changed by automatically adjusting the target angle value, so as to realize the automatic adjustment of the tillage depth of the agricultural implement.

[0015] Preferably, the tilt angle sensor is a single-axis sensor. By using a single-axis sensor, the continuous measurement of the tilt angle and rotational angular velocity of the measured object (lower pull rod or tractor body) in the vertical or inclined plane can be realized, and multi-turn continuous measurement can also be realized.

[0016] A lifting control method based on a dual tilt angle sensor includes the following steps:

[0017] (1) The dual tilt angle sensors respectively obtain the tilt angle values of the lower pull rod and the tractor body;

[0018] (2) The dual tilt angle sensors send the tilt angle values to the main controller, and the main controller receives the tilt angle values; the main controller repeatedly executes the sending and receiving of the tilt angle values of the dual tilt angle sensors;

[0019] (3) The main controller obtains the actual angle value of the three-point hitch system through the two tilt angle values; if the current actual angle value is lower than the target angle value, the main controller issues a rising instruction to control the hydraulic cylinder to extend, and the hydraulic cylinder drives the three-point hitch system to rise. When the three-point hitch system reaches the position corresponding to the target angle value, the main controller issues a stop instruction; if the current actual angle value is higher than the target angle value, the main controller issues a lowering instruction to control the hydraulic cylinder to contract, and the hydraulic cylinder drives the three-point hitch system to lower. When the three-point hitch system reaches the position corresponding to the target angle value, the main controller issues a stop instruction.

[0020] Preferably, the dual tilt angle sensors send the tilt angle values to the main controller, and the main controller samples every 50 ms.

[0021] Preferably, when the tractor enters an inclined plot, the inclination angle value of the tractor body changes, and the main controller dynamically adjusts the target angle value of the agricultural implement through the following formula:

[0022] θ 目标实际 = θ 目标设定 - θ 车身

[0023] where, θ 目标实际 represents the actual angle value of the three-point hitch system, θ 目标设定 represents the target angle value of the set agricultural implement, and θ 车身 represents the inclination angle value of the tractor body. The above method further improves the control accuracy.

[0024] The present invention has the following beneficial effects compared with the prior art:

[0025] 1. The lifting control system based on double inclination sensors in the present invention can collect the relative angle data of the tractor body and the lower link in real time through the double inclination sensors, and realize precise control and real-time monitoring of the lifting process of the agricultural implement through the control of the main controller, so that the three-point hitch system can adapt to complex terrains. At the same time, the lifting control system can adapt to the operation requirements such as rotary tillage, ridging, sowing, and fertilizing, ensuring the stability of the lifting angle and the rapidity of the system response.

[0026] 2. In the lifting control system based on double inclination sensors in the present invention, the double inclination sensors can accurately measure the relative angle data under the condition of large changes in the tilt of the tractor, enabling the three-point hitch system to adapt to a variety of complex operating scenarios and realizing precise lifting control. In addition, the solenoid valve is used to replace the existing electro-hydraulic proportional valve, reducing the hardware cost and maintenance difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a three-dimensional structural schematic diagram of the lifting control system in the present invention.

[0028] Figure 2 is a control principle schematic diagram of the lifting control system in the present invention.

[0029] Figure 3 is a structural schematic diagram of the three-point hitch system in the present invention.

[0030] Figure 4 is a main interface schematic diagram of the display screen in the present invention.

[0031] Figure 5 is a lifting control program flow chart of the lifting control system in the present invention.

[0032] Figure 6 is a geometric structural schematic diagram of the lifting control system in the present invention at different lifting positions. Detailed implementation mode

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described below in conjunction with embodiments and drawings, but the implementation modes of the present invention are not limited thereto.

[0034] Embodiment 1

[0035] Refer to Figures 1 - 3 , this embodiment discloses a lifting control system based on a dual inclination sensor, including a three-point hitch system, a main controller 2, and a dual inclination sensor; the dual inclination sensor is two inclination sensors 1, wherein the three-point hitch system is connected to the tractor body, and the three-point hitch system includes a lower pull rod 6; one of the inclination sensors 1 is installed on the lower pull rod 6 for measuring the inclination angle value of the lower pull rod 6, that is, the angle obtained by this inclination sensor 1; the other inclination sensor 1 is installed on the tractor body for measuring the inclination angle value of the tractor body, that is, the angle obtained by this inclination sensor 1; the dual inclination sensor is connected to the main controller 2 through a CAN bus.

[0036] Refer to Figures 1 - 3 , the working principle of the above-mentioned lifting control system based on a dual inclination sensor is as follows:

[0037] The agricultural implement is installed on the three-point hitch system, and the lifting height of the agricultural implement is (roughly) linearly related to the rotation angle of the lower pull rod 6. By measuring the inclination angle value of the lower pull rod 6 and the inclination angle value of the tractor body through the dual inclination sensor, the relative angle data (the actual angle value of the three-point hitch system) of the tractor body and the lower pull rod 6 can be collected in real time, and through the control of the main controller 2, precise control and real-time monitoring of the lifting process of the agricultural implement can be achieved.

[0038] Refer to Figures 1 - 3 , the lifting control system further includes a hydraulic cylinder 4, a relay, a solenoid valve, a hydraulic oil tank 7, and a hydraulic pump 8; the relay is connected to the main controller 2 and the solenoid valve, the solenoid valve is connected to the hydraulic cylinder 4, the solenoid valve is connected to the hydraulic pump 8, the hydraulic pump 8 is connected to the hydraulic oil tank 7, and the hydraulic oil tank 7 is used to store hydraulic oil. In the above structure, the main controller 2 transmits a control signal to the relay, controls the solenoid valve to work through the relay, the solenoid valve opens, the hydraulic pump 8 pumps hydraulic oil, drives the hydraulic cylinder 4 to move, and makes the pull rod act, realizing the lifting control of the three-point hitch system.

[0039] Refer to Figures 1 - 3, the three-point hitch system further includes a lift arm (AB), an upper pull rod (CD), a lift rod (BF), and a vertical column (BG); wherein, one end of the lift arm is hinged to the tractor body, and the other end is hinged to one end of the lift rod; the other end of the lift rod is hinged to the middle of the lower pull rod 6; the hydraulic cylinder 4 acts on the lift arm; one end of the lower pull rod 6 is hinged to the tractor body, and the other end is hinged to one end of the vertical column; one end of the upper pull rod is hinged to the tractor body, and the other end is hinged to the other end of the vertical column. In the above structure, the hydraulic cylinder 4 drives the lift arm to move, then pulls the lift rod, and drives the lower pull rod 6 to move, thereby completing the lifting action of the agricultural implement.

[0040] Participate Figure 3 , the simplified three-point hitch system is a five-bar linkage mechanism, where the lift arm is denoted as AB, the upper pull rod is denoted as CD, the lower pull rod 6 is denoted as EG, the lift rod is denoted as BF, and the vertical column is denoted as DG. The movement mode of the five-bar linkage mechanism is that the hydraulic cylinder 4 drives the lift arm (AB) to move, and then the lift arm (AB) pulls the lift rod (BF) to drive the lower pull rod 6 (EG) to move, completing the lifting action of the agricultural implement.

[0041] The inclination angle value of the lower pull rod 6 can be set as angle value 1, the inclination angle value of the tractor body can be set as angle value 2, the actual angle value of the three-point hitch system (the included angle of the double inclination sensors) is angle value 3, and angle value 1 minus angle value 2 is the actual angle value of the three-point hitch system. When the three-point hitch system is stationary, angle value 3 will not change due to the tractor's pitching.

[0042] See Figures 1 - 4 , the lift control system further includes a display screen 3, which is used to display in real time the actual angle value of the three-point hitch system (abbreviated as the implement position angle value in the figure), the inclination angle value of the tractor body (abbreviated as the body pitching angle value in the figure), the target angle setting (abbreviated as the implement position angle value in the figure), the target angle value, the manual / automatic mode setting, and the dead zone setting; the actual angle value of the three-point hitch system is the absolute value of the value obtained by subtracting the inclination angle value of the tractor body from the inclination angle value of the lower pull rod 6. By setting the display screen 3, various information can be displayed and operations and settings can be performed through the display screen 3, which is very convenient to use. The manual / automatic mode setting means that there are a manual mode button and an automatic mode button on the display screen. By clicking on the position of the manual mode button, the manual mode is selected, and by clicking on the position of the automatic mode button, the automatic mode is selected. The display screen has functions such as target angle setting, manual / automatic mode setting, and dead zone setting.

[0043] See Figures 1 - 4, the main controller 2 continuously obtains the tilt angle value of the lower link 6 and the tilt angle value of the tractor body in real time, and then calculates the actual angle value of the three-point hitch system (i.e., the actual angle value of the agricultural implement) based on the two tilt angle values. By calculating the difference between the actual angle value and the target angle value, and making a judgment based on the sign of the difference, a control signal is obtained. The control signal is transmitted to the relay, and the relay controls the solenoid valve to work, thereby controlling the movement of the lower link 6, achieving the lifting control of the three-point hitch system, and finally moving the three-point hitch system to the position corresponding to the target angle value.

[0044] See Figures 1 - 4 , the dual inclination sensors transmit the inclination angle values to the main controller 2 via the CAN bus. The integrated lifting control program is loaded in the main controller 2, and the main controller 2 controls the lifting and lowering of the three-point hitch system through the lifting control program. The remote control can wirelessly control the lifting and lowering of the three-point hitch system.

[0045] See Figures 1 - 4 , in this embodiment, the lifting control system has a manual / auto mode:

[0046] On the main page of the display screen 3, the user can touch the dead zone setting (button) to adjust the dead zone value. The range of the dead zone value is set between 1° and 10° to meet the requirements of different operation precisions, and the default dead zone value is set to 5°. In fine operations (such as seeding operations), the dead zone can be set to less than 5°. In rough operations (such as soil turning operations), the dead zone can be set to greater than 5°. The main controller 2 continuously obtains Angle Value 1 and Angle Value 2, and takes the absolute value of the difference between the two values, which is the actual angle value of the agricultural implement. In the lifting control program, the difference between the actual angle value and the target angle value is calculated, and a judgment is made based on the sign of the deviation value to obtain a control signal. The control signal is transmitted to the relay, thereby controlling the movement of the three-point hitch system. The three-point hitch system moves to the corresponding angle position and stops within the range of the dead zone value, and continues to adjust outside the range of the dead zone value, forming a closed-loop control until the three-point hitch system moves to the position corresponding to the target angle value.

[0047] See Figures 1 - 4 , in the initial state, the three-point hitch system is in the raised state and is located at the angle position of the upper limit angle.

[0048] See Figures 1 - 4 , the manual mode is suitable for use when the plot is ideal. The specific steps of the manual mode are as follows:

[0049] Select the manual mode on the display screen 3 (the user clicks the manual mode on the home page of the display screen 3), then touch the target angle setting on the display screen 3 and input the target angle value. The range of the target angle value can be manually changed, and the default is -5° to 35°; if the input range of the target angle value is greater than the default range of the target angle value, a prompt will be given to re-enter. After the input is completed, click OK and return to the main page; then, the user clicks the "Lower the implement" button on the display screen 3. At this time, the main controller 2 calculates the difference between the actual angle value and the target angle value to obtain a control signal, transmits the control signal to the relay, controls the solenoid valve to work through the relay, and the hydraulic cylinder 4 drives the lower pull rod 6 to move, so as to control the three-point hitch system to perform a lowering action until the agricultural implement moves to the position corresponding to the target angle value (the set target angle); after the operation is completed, click the "Raise the implement" button on the display screen 3, and the three-point hitch system moves to the position corresponding to the initial state.

[0050] See Figures 1 - 4 , the specific steps of the automatic mode are as follows: Select the automatic mode on the display screen 3 (the user clicks the automatic mode on the home page of the display screen 3), then touch the target angle setting on the display screen 3 and input the target angle value. The range of the target angle value can be manually changed, and the default is -5° to 35°; if the input range of the target angle value is greater than the default range of the target angle value, a prompt will be given to re-enter. After the input is completed, click OK and return to the main page; then, the user clicks the "Raise the implement" button on the display screen 3. At this time, the main controller 2 calculates the difference between the actual angle value and the target angle value to obtain a control signal, transmits the control signal to the relay, controls the solenoid valve to work through the relay, and the hydraulic cylinder 4 drives the lower pull rod 6 to move, so as to control the three-point hitch system to perform a lowering action until the agricultural implement moves to the position corresponding to the target angle value (the set target angle). Then, when the tractor body tilts, the main controller 2 automatically adjusts the target angle value according to the tilt angle value of the tractor body obtained in real time; after the operation is completed, click the "Raise the implement" button on the display screen 3. The purpose is that when the tractor body tilts and the tillage depth of the agricultural implement changes, the position of the agricultural implement is changed by automatically adjusting the target angle value, so as to realize the automatic adjustment of the tillage depth of the agricultural implement.

[0051] See Figures 1 - 3 , the inclination sensor 1 is a single-axis sensor. By using a single-axis sensor, the continuous measurement of the inclination angle and rotational angular velocity of the measured object (the lower pull rod 6 or the tractor body) in the vertical or inclined plane can be realized, and multi-turn continuous measurement can also be realized.

[0052] Embodiment 2

[0053] See Figures 1 - 5, this embodiment discloses a lifting control method based on a dual inclination sensor. This method is applied to the lifting control system described in Embodiment 1 and includes the following steps:

[0054] (1) The dual inclination sensors respectively obtain the inclination angle values of the lower link 6 and the tractor body.

[0055] (2) The dual inclination sensors send the inclination angle values to the main controller 2, and the main controller 2 receives the inclination angle values; the main controller 2 repeatedly executes the sending and receiving of the inclination angle values of the dual inclination sensors.

[0056] (3) The main controller 2 obtains the actual angle value of the three-point suspension system from the two inclination angle values; if the current actual angle value is lower than the target angle value, the main controller 2 issues a rising command to control the hydraulic cylinder 4 to extend, and the hydraulic cylinder 4 drives the three-point suspension system to rise. When the three-point suspension system reaches the position corresponding to the target angle value, the main controller 2 issues a stop command; if the current actual angle value is higher than the target angle value, the main controller 2 issues a descending command to control the hydraulic cylinder 4 to contract, and the hydraulic cylinder 4 drives the three-point suspension system to descend. When the three-point suspension system reaches the position corresponding to the target angle value, the main controller 2 issues a stop command. At the same time, the dead zone position obtained by calibration eliminates the micro-motion interference. The upper computer can also send the target angle value to the main controller 2 according to the operation requirements obtained from the path planning, and the main controller 2 is the chassis integrated controller.

[0057] In step (3), when the main controller 2 issues a rising command, after the relay receives the rising command, it controls the solenoid valve to open, and the hydraulic oil enters the hydraulic cylinder, and the hydraulic cylinder 4 drives the three-point suspension system to rise. When the main controller 2 issues a descending command, after the relay receives the descending command, it controls the solenoid valve to open, and the hydraulic oil flows reversely, and the hydraulic cylinder 4 drives the three-point suspension system to descend.

[0058] See Figures 1 - 5 , when the tractor enters an inclined plot, the inclination angle value of the tractor body changes, and the main controller 2 dynamically adjusts the target angle value of the agricultural implement through the following formula:

[0059] θ 目标实际 =θ 目标设定 -θ 车身

[0060] Among them, θ 目标实际 represents the actual angle value of the three-point suspension system, θ 目标设定 represents the set target angle value of the agricultural implement, and θ 车身 represents the inclination angle value of the tractor body. The above method further improves the control accuracy.

[0061] See Figure 6, for the lifting control method in this embodiment, it is necessary to establish a geometric model of the lifting control system. The three-point hitch system of the tractor can be simplified to a long rod rotating around a fixed point. The movement laws of the lifting or lowering of the agricultural implement and the tilting of the tractor body can be referred to Figure 4 as shown. Among them, point O is the connection point between the simplified three-point hitch system and the tractor body. T1, T2, and T3 represent three different lifting positions.

[0062] Refer to Figures 1 - 4 and Figure 6 , the inclination sensor 1 reads the angle relative to the absolute horizontal line. A1 respectively represents the inclination angle value read by the inclination sensor 1 when the three-point hitch system is in the T2 position, A2 respectively represents the inclination angle value read by the inclination sensor 1 when the three-point hitch system is in the T1 position, A3 respectively represents the inclination angle value read by the inclination sensor 1 when the three-point hitch system is in the T3 position, and A4 respectively represents the inclination angle value read by the inclination sensor 1 when the three-point hitch system is in the T1 position, which is the inclination angle value read by the inclination sensor 1 of the tractor body. The angle differences generated at the three lifting positions of T1, T2, and T3 are D2, D1, and D3. Among them, D2, D1, and D3 respectively reflect the angle of the lower pull rod 6 relative to the tractor body (the actual angle value of the three-point hitch system), that is, the lifting angle. The relational expression between the lifting angle and the two inclination sensors 1 is:

[0063]

[0064] Refer to Figures 1 - 4 , the double inclination sensors send the inclination angle values to the main controller 2, and the main controller samples every 50 ms; processes according to the lifting control program, and controls the telescopic movement of the hydraulic cylinder 4 to realize the up and down movement of the lower pull rod 6.

[0065] Refer to Figure 5 , the lifting control program realizes functions such as data acquisition, closed-loop control, and actuator drive (solenoid valve) through embedded software. The specific steps of the lifting control program are:

[0066] S1. Parameter initialization: Initialize the lifting control parameters in the main function of the program. The lifting control parameters include the upper limit angle (linmit_up_angle), the lower limit angle (linmit_down_angle), and the dead zone (dead_angle);

[0067] S2. Load the lifting control parameters;

[0068] S3. Double inclination sensor data acquisition: The double inclination sensors respectively acquire the inclination angle value of the lower pull rod 6 and the inclination angle value of the tractor body;

[0069] S4. Calculate the actual angle value α: Obtain the actual angle value α of the three-point suspension system from the two tilt angle values;

[0070] S5. Select the manual / automatic mode:

[0071] When the manual mode is selected, the user inputs the target angle value θ. If the lower limit angle < θ < the upper limit angle is satisfied, step S6 is executed. If the lower limit angle < θ < the upper limit angle is not satisfied, the target angle value θ is input again;

[0072] When the automatic mode is selected, the target angle value is dynamically compensated, and step S6 is executed;

[0073] S6. Calculate the deviation: Calculate the difference between the actual angle value and the target angle value;

[0074] S7. If |θ - α| is less than the dead zone value, the three-point suspension system (abbreviation: suspension) remains in the stopped state, and step S3 is executed; otherwise, the main controller 2 controls the three-point suspension system to rise or fall, and the change of the actual angle value is monitored in real time until the suspension system moves to the position corresponding to the target angle value.

[0075] See Figure 5 , in step S4, the real-time status is updated: the actual angle value, that is, the angle value 3 (diff_angle), is transmitted to the main controller 2 in real time every 50 ms.

[0076] See Figure 5 , after the lifting control program is initialized and the target angle value is input, the three-point suspension system starts to move towards the target angle value. The tilt angle value of the tilt sensor 1 is fed back to the main controller 2 in real time. When the error between the actual angle value and the target angle value is less than the dead zone range, the three-point suspension system stays at the current position. The main controller 2 receives the tilt angle values sent by the dual tilt sensors, analyzes the current position where the three-point suspension system stays according to the tilt angle values. At the same time, the main controller 2 can receive the instructions sent by the display screen 3, control the operation of the entire lifting control system, and set the basic parameters required for the operation of the lifting control system.

[0077] In the lifting control system based on dual tilt sensors in this embodiment, the relative angle data between the tractor body and the lower pull rod is collected in real time through the dual tilt sensors, and through the control of the main controller, precise control and real-time monitoring of the lifting process of agricultural implements are realized, so that the three-point suspension system can adapt to complex terrains. At the same time, the lifting control system can adapt to the operation requirements such as rotary tillage, ridging, sowing, and fertilizing, ensuring the stability of the lifting angle and the rapidity of the system response.

[0078] In the lifting control system based on dual inclination sensors in this embodiment, the dual inclination sensors can accurately measure relative angle data under the condition of large tilting changes of the tractor, enabling the three-point hitch system to adapt to various complex operation scenarios and achieve precise lifting control. Additionally, solenoid valves are used to replace the existing electro-hydraulic proportional valves, reducing the hardware cost and maintenance difficulty.

[0079] By introducing a closed-loop control and a predictive compensation algorithm, the action inertia and overshoot phenomenon of the hydraulic cylinder are effectively suppressed. The response time of the lifting control system is shortened, improving the operation efficiency.

[0080] The above is a preferred embodiment of the present invention. However, the embodiments of the present invention are not limited by the above content. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A lifting control system based on dual inclination sensors, characterized in that, It includes a three-point suspension system, a main controller, and a dual inclination sensor; wherein, the three-point suspension system is connected to the tractor body, and the three-point suspension system includes a lower link; one of the inclination sensors is installed on the lower link for measuring the inclination angle value of the lower link; the other inclination sensor is installed on the tractor body for measuring the inclination angle value of the tractor body; the dual inclination sensor is connected to the main controller through a CAN bus.

2. The lifting control system according to claim 1, characterized in that, The lifting control system further includes a hydraulic cylinder, a relay, and a solenoid valve; the relay is connected to the main controller and the solenoid valve, and the solenoid valve is connected to the hydraulic cylinder.

3. The lifting control system according to claim 2, wherein The three-point suspension system further includes a lift arm, an upper link, a lift rod, and a column; wherein, one end of the lift arm is hinged to the tractor body, and the other end is hinged to one end of the lift rod; the other end of the lift rod is hinged to the middle of the lower link; the hydraulic cylinder acts on the lift arm; one end of the lower link is hinged to the tractor body, and the other end is hinged to one end of the column; one end of the upper link is hinged to the tractor body, and the other end is hinged to the other end of the column.

4. The lifting control system according to claim 3, wherein The lifting control system further includes a display screen, which is used to display in real time the actual angle value of the three-point suspension system, the inclination angle value of the tractor body, the target angle setting, the target angle value, the manual / automatic mode setting, and the dead zone setting; the actual angle value of the three-point suspension system is the absolute value of the value obtained by subtracting the inclination angle value of the tractor body from the inclination angle value of the lower link.

5. The lift control system according to claim 4, characterized in that, In the initial state, the three-point suspension system is in the raised state, and the three-point suspension system is located at the angular position of the upper limit angle; the specific steps of the manual mode are as follows: Select the manual mode on the display screen, and then input the target angle value on the display screen. The main controller calculates the difference between the actual angle value and the target angle value to obtain a control signal, transmits the control signal to the relay, controls the solenoid valve to work through the relay, and the hydraulic cylinder drives the lower link to move, so as to control the three-point suspension system to perform a lowering action until the agricultural implement moves to the position corresponding to the target angle value.

6. The lifting control system according to claim 5, wherein The specific steps of the automatic mode are as follows: Select the automatic mode on the display screen. The other steps of the automatic mode are the same as the specific steps of the manual mode. The difference is that after the agricultural implement moves to the position corresponding to the target angle value, when the tractor body tilts, the main controller automatically adjusts the target angle value according to the inclination angle value of the tractor body obtained in real time.

7. The lift control system according to claim 5, characterized in that The inclination sensor is a single-axis sensor.

8. A lifting control method based on a dual-inclination sensor, characterized in that, The lifting control method is applied to the lifting control system according to any one of claims 2-3, and includes the following steps: (1) The dual inclination sensor respectively obtains the inclination angle values of the lower link and the tractor body. (2) The dual inclination sensor sends the inclination angle value to the main controller, and the main controller receives the inclination angle value; the main controller repeatedly executes the sending and receiving of the inclination angle value of the dual inclination sensor. (3) The main controller obtains the actual angle value of the three-point hitch system based on the two tilt angle values. If the current actual angle value is lower than the target angle value, the main controller issues a rising command to control the hydraulic cylinder to extend. The hydraulic cylinder drives the three-point hitch system to rise. When the three-point hitch system reaches the position corresponding to the target angle value, the main controller issues a stop command. If the current actual angle value is higher than the target angle value, the main controller issues a descending command to control the hydraulic cylinder to contract. The hydraulic cylinder drives the three-point hitch system to descend. When the three-point hitch system reaches the position corresponding to the target angle value, the main controller issues a stop command.

9. The lifting control method according to claim 8, characterized in that, The dual tilt sensors send the tilt angle values to the main controller, and the main controller samples every 50 ms.

10. The lifting control method according to claim 8, wherein When the tractor enters a sloping field, the tilt angle value of the tractor body changes, and the main controller dynamically adjusts the target angle value of the agricultural implement through the following formula: θ 目标实际 = θ 目标设定 - θ 车身 Among them, θ 目标实际 represents the actual angle value of the three-point suspension system, θ 目标设定 represents the target angle value of the agricultural implement set, θ 车身 represents the tilt angle value of the tractor body.

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