Tractor steering control method and device

Abstract

The invention relates to the technical field of tractor steering, in particular to a tractor steering control method. The method comprises the following steps: step 1, steering angle feedback control: monitoring a steering angle in real time through an angle sensor mounted on a steering oil cylinder, feeding data back to a microcontroller through a control system, adjusting the opening degree of an electric control valve in the power-assisted steering gear, and changing oil flows on two sides of the steering oil cylinder, so as to accurately control the steering angle; and 2, proportional control is conducted, specifically, a proportional control algorithm is adopted, the oil flow is adjusted according to the deviation of the steering angle, the steering angle rapidly and stably reaches the target value, and the core of proportional control is to maintain the difference of oil pressure on the two sides of an oil cylinder and adjust the hydraulic flow and pressure. The key of the design of the steering control system of the tractor is to accurately control the movement of the oil cylinder and ensure that the steering angle can be stably and flexibly adjusted under different speeds, loads and ground conditions. By optimizing the design of the hydraulic system and adopting an advanced control algorithm and an intelligent compensation strategy, the steering performance can be remarkably improved, the energy consumption can be reduced, and better user experience can be provided.

Description

Technical Field

[0001] The invention relates to the technical field of tractor steering, and in particular to a tractor steering control method and a device thereof. Background Art

[0002] Tractors are indispensable mechanical equipment in agricultural production and can be used for tilling land, sowing, fertilizing, transportation, etc. The tractor is mainly composed of a travel system, a working device system, a steering system, etc. The steering system is mainly hydraulically driven and consists of a steering wheel, a steering column, a steering oil pump, a steering gear, a steering cylinder, a steering oil pipe, a steering axle and tires. When not steering, the hydraulic oil of the steering oil pump flows back to the fuel tank through the middle position of the steering gear; when steering is required, the steering gear is controlled by the steering wheel to be in the working position, and the hydraulic oil of the steering oil pump flows into the steering cylinder through the oil inlet branch of the working position of the steering gear, thereby driving the steering axle and tires, so that the tractor can adjust the driving direction as needed;

[0003] The existing electronically controlled steering device is mainly composed of proportional control elements (proportional reversing valves) for controlling flow, hydraulic locks, relief valves, control switches and other components. If the tractor is detected to be not operating on the specified route during normal operation, the navigation controller will issue a command to make the proportional reversing valve work in the corresponding working position, and part of the oil from the steering oil pump will flow back to the oil tank through the middle position of the steering gear, and the other part of the oil will enter the steering oil cylinder through the oil inlet branch of the working position of the proportional reversing valve, thereby driving the steering axle, steering wheels and other components to achieve steering, complete the adjustment of the driving direction, and make the tractor work on the specified route.

[0004] However, in the current tractor steering control system, it is impossible to accurately control the operation of the steering cylinder, especially under the influence of the tractor's own driving speed and driving environment, the steering angle cannot be accurately adjusted.

[0005] Therefore, a tractor steering control method and device are proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a tractor steering control method and device. The key to the design of the tractor steering control system is to accurately control the movement of the oil cylinder to ensure that the steering angle can be stably and flexibly adjusted under different speeds, loads and ground conditions. By optimizing the design of the hydraulic system, adopting advanced control algorithms and intelligent compensation strategies, the steering performance can be significantly improved, energy consumption can be reduced, and a better user experience can be provided to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a tractor steering control method, comprising the following steps;

[0008] Step 1: Steering angle feedback control: The steering angle is monitored in real time by an angle sensor installed on the steering cylinder. The data is fed back to the microcontroller through the control system to adjust the opening of the electronic control valve in the power steering gear and change the oil flow on both sides of the steering cylinder, thereby accurately controlling the steering angle.

[0009] Step 2: Proportional control: Use proportional control algorithm to adjust the oil flow according to the deviation of the steering angle so that the steering angle reaches the target value quickly and smoothly. The core of proportional control is to maintain the difference in oil pressure on both sides of the cylinder and adjust the hydraulic flow and pressure;

[0010] Step 3: Speed ​​compensation: The steering performance of the tractor varies at different speeds. By adding a speed compensation strategy to the control algorithm, the vehicle speed signal is added to avoid instability caused by over-fast steering at high speeds, while maintaining sufficient sensitivity and response speed at low speeds.

[0011] Step 4: Load compensation: Depending on the load of the tractor, the output of the hydraulic system will also change. The load sensing control strategy is adopted to adjust the hydraulic flow and pressure in real time according to the load changes of the cylinder to ensure a stable steering angle and response speed;

[0012] Step 5: Closed-loop control: Based on the steering angle feedback, the opening of the electronically controlled valve is adjusted through the PID control algorithm to accurately control the movement of the steering cylinder;

[0013] Step 6: Fuzzy control: In complex working environments, such as different ground surfaces and changes in turning radius, a fuzzy control algorithm is used to determine changes in the steering angle using fuzzy logic rules and adjust the working state of the cylinder.

[0014] Preferably, in step 1, steering angle feedback control, a steering angle sensor is used to feed back the steering angle θ in real time, and the feedback signal is used to calculate the error and adjust the opening of the control valve, and the hydraulic flow and pressure of the cylinder are adjusted according to the steering angle error Δθ to form a closed-loop control. In the control strategy, a PID controller is used to calculate the required flow and pressure of the cylinder, and the formula is:

[0015]

[0016] Where: u(t) is the control output, i.e. the oil pressure or oil flow required by the steering cylinder, e(t) = θ target -θ(t) is the steering angle error, K p , K i , K d are proportional, integral and differential gains, θ target is the desired steering angle and θ(t) is the current steering angle.

[0017] Preferably, in the step 3, speed compensation, the control formula may introduce a vehicle speed compensation factor V:

[0018]

[0019] Where: f(v) is the speed compensation function, which is a linear or nonlinear function.

[0020] Preferably, in step 2, proportional control, the hydraulic flow Q and the control signal v ctrl The relationship between them is:

[0021] Q=βv ctrl ΔP

[0022] Where: β is the flow gain of the valve, ΔP is the pressure difference across the valve, v ctrl It is the control signal, which is adjusted by PID control.

[0023] Preferably, the step 4, load compensation, describes the hysteresis by introducing a dynamic model:

[0024] θ compensated (t) = θ(t) + γ (θ(t) - θ prev (t))

[0025] Where: γ is the hysteresis compensation coefficient. θ prev (t) is the steering angle at the previous moment.

[0026] A tractor steering control device comprises a hydraulic suspension body, the two sides of the hydraulic suspension body are respectively rotatably connected with a left front axle and a right front axle, two groups of steering oil cylinders are fixed on the front side of the hydraulic suspension body, the output shafts of the two groups of steering oil cylinders are respectively rotatably connected with the left front axle and the right front axle to control the deflection of the left front axle and the right front axle at the two ends of the hydraulic suspension body, and a power steering device with a built-in electric control valve is also arranged on the rear side of the hydraulic suspension body, and the output end of the power steering device is connected to the steering oil cylinder oil circuit through an oil pipe;

[0027] The steering cylinder includes a hydraulic cylinder and a hydraulic rod, one end of the hydraulic rod extends into the hydraulic cylinder, and one end of the hydraulic rod located in the hydraulic cylinder is fixed with a cylinder plug through a flange bolt connection, the outer wall of the cylinder plug is in contact with the inner wall of the hydraulic cylinder, and the connecting pipe symmetrically fixed outside the hydraulic cylinder has a joint 1 and a joint 2 connected to the oil pipe, the cylinder plug is located between the joint 1 and the joint 2, and the movable distance of the cylinder plug is between the joint 1 and the joint 2, and the end of the hydraulic rod away from the cylinder plug is fixedly connected with a collar rotatably connected to the left front axle and the right front axle.

[0028] Preferably, the outer ring of the hydraulic cylinder is fixedly connected with a plurality of heat dissipating fins with a hollow structure at equal distances, and the outer movably connected with the heat dissipating fins is connected with a cleaning scraper, the cleaning scraper is designed with an arc structure and wrapped around the surface of the heat dissipating fins and distributed perpendicularly to the heat dissipating fins, the cleaning scraper is made of a magnetic metal material, and the cylinder plug is internally embedded with a strong magnetic plate, and the strong magnetic plate is magnetically attracted to the cleaning scraper.

[0029] Preferably, the outside of the hydraulic rod is respectively sleeved with a fixing plate three and a fixing plate two, the fixing plate two is movably connected to the hydraulic rod, the fixing plate three is fixedly connected to the hydraulic rod, and the outside of the hydraulic rod located between the fixing plate three and the fixing plate two is sleeved with a threaded airbag, and the two ends of the threaded airbag are respectively fixedly connected to the fixing plate three and the fixing plate two.

[0030] Preferably, one end of the hydraulic rod close to the threaded airbag is fixedly connected to a fixing plate 1, a jet pipe is connected between the fixing plate 2 and the fixing plate 1, and one end of the jet pipe is connected to the threaded airbag, and jet heads are provided in a circular shape at equal distances on one side of the fixing plate 1 away from the jet pipe, the other end of the jet pipe is connected to the jet head, and the jet head is located between adjacent heat dissipation fins.

[0031] Preferably, an annular magnet is embedded inside the second fixing plate, a water-cooling air bag is fixed between the second fixing plate and the first fixing plate, and the water-cooling air bag is sleeved on the outside of the hydraulic rod, the annular magnet and the adjacent surface of the strong magnetic plate magnetically repel each other, and a cooling pipe is symmetrically fixed on one side of the first fixing plate close to the heat dissipation fins, one end of the cooling pipe is connected to the water-cooling air bag, and the other end is connected to the heat dissipation fins, the adjacent heat dissipation fins are connected end to end, and a spring is fixed inside the water-cooling air bag.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. The key to the design of the tractor's steering control system is to accurately control the movement of the oil cylinder to ensure that the steering angle can be adjusted stably and flexibly under different speeds, loads and ground conditions. By optimizing the design of the hydraulic system, using advanced control algorithms and intelligent compensation strategies, the steering performance can be significantly improved, energy consumption can be reduced, and a better user experience can be provided;

[0034] 2. Optimizing the steering control principle and the design of the hydraulic system can improve the steering accuracy, response speed and energy efficiency of the tractor. The introduction of technologies such as closed-loop control (such as PID control), speed compensation, hysteresis compensation, dynamic hydraulic control and variable displacement pumps can effectively respond to various working conditions and improve the stability and reliability of the system. In the future, with the development of autonomous driving technology and intelligent control algorithms, the steering control system is expected to become more intelligent and achieve more sophisticated dynamic adjustment and energy efficiency optimization;

[0035] 3. By designing the tractor steering control device, the steering cylinder body and the hydraulic oil can be efficiently cooled and dissipated, while the hydraulic rod of the steering cylinder body can be protected to reduce the adhesion of dust and impurities, and reduce the probability of dust following the hydraulic rod into the hydraulic rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 is a flow chart of the tractor steering control method of the present invention;

[0038] Figure 2 A comparative experimental data table of steering control optimization of the present invention;

[0039] Figure 3 A structural view of a tractor steering control device of the present invention;

[0040] Figure 4 It is a structural view of the steering cylinder of the present invention;

[0041] Figure 5 It is a rear view of the steering cylinder of the present invention;

[0042] Figure 6 It is a front view of the steering cylinder of the present invention;

[0043] Figure 7 A top view of the steering cylinder of the present invention;

[0044] Figure 8 It is a cross-sectional view of the steering cylinder of the present invention.

[0045] Description of reference numerals:

[0046] 1. Hydraulic suspension body; 2. Steering cylinder; 3. Left front axle; 4. Right front axle; 5. Power steering; 6. Hydraulic cylinder; 7. Connector 1; 8. Connector 2; 9. Cooling fins; 10. Cleaning scraper; 11. Fixed plate 1; 12. Cooling pipe; 13. Jet pipe; 14. Water-cooled airbag; 15. Fixed plate 2; 16. Threaded airbag; 17. Fixed plate 3; 18. Ring; 19. Hydraulic rod; 20. Ring magnet; 21. Spring; 22. Cylinder plug; 23. Strong magnetic plate; 24. Jet head. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] See also Figures 1 to 8 , the present invention provides a technical solution:

[0049] A tractor steering control method comprises the following steps:

[0050] Step 1: Steering angle feedback control: The steering angle is monitored in real time by an angle sensor installed on the steering cylinder. The data is fed back to the microcontroller through the control system to adjust the opening of the electronic control valve in the power steering gear and change the oil flow on both sides of the steering cylinder, thereby accurately controlling the steering angle.

[0051] Step 2: Proportional control: Use proportional control algorithm to adjust the oil flow according to the deviation of the steering angle so that the steering angle reaches the target value quickly and smoothly. The core of proportional control is to maintain the difference in oil pressure on both sides of the cylinder and adjust the hydraulic flow and pressure;

[0052] Step 3: Speed ​​compensation: The steering performance of the tractor varies at different speeds. By adding a speed compensation strategy to the control algorithm, the vehicle speed signal is added to avoid instability caused by over-fast steering at high speeds, while maintaining sufficient sensitivity and response speed at low speeds.

[0053] Step 4: Load compensation: Depending on the load of the tractor, the output of the hydraulic system will also change. The load sensing control strategy is adopted to adjust the hydraulic flow and pressure in real time according to the load changes of the cylinder to ensure a stable steering angle and response speed;

[0054] Step 5: Closed-loop control: Based on the steering angle feedback, the opening of the electronically controlled valve is adjusted through the PID control algorithm to accurately control the movement of the steering cylinder;

[0055] Step 6: Fuzzy control: In complex working environments, such as different ground surfaces and changes in turning radius, a fuzzy control algorithm is used to determine changes in the steering angle using fuzzy logic rules and adjust the working state of the cylinder.

[0056] Specifically, the steering system drives the steering device through a hydraulic cylinder to control the front wheel angle. The control of the steering angle depends on the difference in oil flow and oil pressure in the hydraulic system. To accurately control the steering angle, it is necessary to adjust the opening of the control valve in combination with the actual steering angle feedback. The most common optimization method is to combine closed-loop control (such as PID control) with proportional control. The step one, steering angle feedback control, uses a steering angle sensor to provide real-time feedback on the steering angle θ. The feedback signal is used to calculate the error and adjust the opening of the control valve. The hydraulic flow and pressure of the cylinder are adjusted according to the steering angle error Δθ to form a closed-loop control. In the control strategy, a PID controller is used to calculate the required flow and pressure of the cylinder. The formula is:

[0057]

[0058] Where: u(t) is the control output, i.e. the oil pressure or oil flow required by the steering cylinder, e(t) = θ target -θ(t) is the steering angle error, K p , K i , K d are proportional, integral and differential gains, θ target is the desired steering angle, θ(t) is the current steering angle, and this control method can effectively reduce the steering angle deviation caused by errors and dynamic changes.

[0059] Specifically, in step 3, speed compensation, the adjustment of the steering angle is not only related to the flow of the oil cylinder, but also closely related to the driving speed vv of the tractor. When driving at high speed, the change of the steering angle should be more gradual to avoid excessive control; while when driving at low speed, higher sensitivity is required, and the control formula can introduce the vehicle speed compensation factor V:

[0060]

[0061] Where: f(v) is the speed compensation function, which is a linear or nonlinear function, and its typical form is:

[0062] This formula means that at low speeds, the compensation factor is larger and the system response is more sensitive; at high speeds, the compensation factor becomes smaller and the response becomes smoother.

[0063] Specifically, the response speed of the hydraulic system directly determines the sensitivity and accuracy of the steering system. Traditional proportional valve control may have large delays and lags. The response speed of the system can be improved by using servo valves or dynamic proportional valves. These valves can achieve faster and more delicate adjustments by accurately controlling the flow of hydraulic oil. In step 2, proportional control, the hydraulic flow Q is proportional to the control signal v ctrl The relationship between them is:

[0064] Q=βv ctrl ΔP

[0065] Where: β is the flow gain of the valve, ΔP is the pressure difference across the valve, v ctrl It is the control signal, which is adjusted by PID control.

[0066] Specifically, the hysteresis effect of the hydraulic system will lead to a decrease in control accuracy, especially when switching between forward and reverse steering. In order to compensate for the hysteresis effect, a compensation model can be used. The step 4, load compensation, describes the hysteresis by introducing a dynamic model:

[0067] θ compensated (t) = θ(t) + γ (θ(t) - θ prev (t))

[0068] Where: γ is the hysteresis compensation coefficient. θ prev (t) is the steering angle at the previous moment. This compensation method can reduce the steering accuracy error caused by the hysteresis of the hydraulic system and improve the stability of the system.

[0069] A tractor steering control device comprises a hydraulic suspension body 1, wherein the left front axle 3 and the right front axle 4 are rotatably connected to the two sides of the hydraulic suspension body 1, two groups of steering cylinders 2 are fixed to the front side of the hydraulic suspension body 1, and the output shafts of the two groups of steering cylinders 2 are rotatably connected to the left front axle 3 and the right front axle 4 respectively for controlling the deflection of the left front axle 3 and the right front axle 4 at the two ends of the hydraulic suspension body 1, and a power steering device 5 with a built-in electric control valve is also arranged at the rear side of the hydraulic suspension body 1, and the output end of the power steering device 5 is connected to the steering cylinder 2 oil circuit for transmission through an oil pipe;

[0070] The steering cylinder 2 includes a hydraulic cylinder 6 and a hydraulic rod 19, one end of the hydraulic rod 19 extends into the hydraulic cylinder 6, and one end of the hydraulic rod 19 located in the hydraulic cylinder 6 is fixed with a cylinder plug 22 through a flange bolt connection, the outer wall of the cylinder plug 22 is in contact with the inner wall of the hydraulic cylinder 6, and the external symmetrical fixed connecting pipe of the hydraulic cylinder 6 has a joint 7 and a joint 8 connected to the oil pipe, the cylinder plug 22 is located between the joint 1 7 and the joint 2 8, and the movable distance of the cylinder plug 22 is between the joint 1 7 and the joint 2 8, and the end of the hydraulic rod 19 away from the cylinder plug 22 is fixedly connected with a collar 18 rotatably connected to the left front axle 3 and the right front axle 4.

[0071] Specifically, the outer ring of the hydraulic cylinder 6 is fixedly connected with a plurality of hollow heat sink fins 9 at equal distances, and the outer movably connected with the heat sink fins 9 is connected with a cleaning scraper 10. The cleaning scraper 10 is designed with an arc structure and is wrapped around the surface of the heat sink fins 9 and is distributed perpendicular to the heat sink fins 9. The cleaning scraper 10 is made of a magnetic metal material. The cylinder plug 22 is internally embedded with a strong magnetic plate 23, and the strong magnetic plate 23 is magnetically attracted to the cleaning scraper 10.

[0072] Specifically, the outside of the hydraulic rod 19 is respectively sleeved with a fixing plate three 17 and a fixing plate two 15, the fixing plate two 15 is movably connected to the hydraulic rod 19, the fixing plate three 17 is fixedly connected to the hydraulic rod 19, and the outside of the hydraulic rod 19 located between the fixing plate three 17 and the fixing plate two 15 is sleeved with a threaded airbag 16, and the two ends of the threaded airbag 16 are respectively fixedly connected to the fixing plate three 17 and the fixing plate two 15.

[0073] Specifically, one end of the hydraulic rod 19 close to the threaded airbag 16 is fixedly connected to a fixing plate 11, a jet pipe 13 is connected between the fixing plate 2 15 and the fixing plate 11, and one end of the jet pipe 13 is connected to the threaded airbag 16, and a jet head 24 is provided in a circular shape at equal distances on one side of the fixing plate 11 away from the jet pipe 13, the other end of the jet pipe 13 is connected to the jet head 24, and the jet head 24 is located between adjacent heat dissipation fins 9.

[0074] Specifically, an annular magnet 20 is embedded inside the fixing plate 15, a water-cooling airbag 14 is fixed between the fixing plate 15 and the fixing plate 1 11, and the water-cooling airbag 14 is sleeved on the outside of the hydraulic rod 19, the annular magnet 20 and the adjacent surface of the strong magnetic plate 23 magnetically repel each other, and a cooling pipe 12 is symmetrically fixedly connected to one side of the fixing plate 11 close to the heat dissipation fin 9, one end of the cooling pipe 12 is connected to the water-cooling airbag 14, and the other end is connected to the heat dissipation fin 9, and the adjacent heat dissipation fins 9 are connected end to end, and a spring 21 is fixed inside the water-cooling airbag 14.

[0075] Working principle: When the oil pipe is controlled by the power steering device 5 to inject hydraulic oil into the hydraulic cylinder 6 through the joint 7, the cylinder plug 22 in the hydraulic cylinder 6 moves to the right in the hydraulic rod 19 under the pressure of the hydraulic oil, and pushes the hydraulic rod 19 connected to the cylinder plug 22 to extend outward in the hydraulic rod 19, and drives the left front axle 3 or the right front axle 4 to deflect and steer through the collar 18 connected to the left front axle 3 or the right front axle 4 at one end of the hydraulic rod 19. The steering of the left front axle 3 or the right front axle 4 is achieved by controlling the steering cylinder 2 corresponding to the left front axle 3 and the right front axle 4. In the process of the hydraulic rod 19 extending outward, the hydraulic rod 19 is fixed to the hydraulic rod 19. The fixed fixing plate 3 17 moves together and pulls the threaded airbag 16 to extend. The surface of the threaded airbag 16 is provided with an air hole with a built-in one-way valve, and the outside air is sucked into the threaded airbag 16 through the air hole. When the power steering device 5 controls the oil pipe to inject hydraulic oil into the joint 2 8, similarly, the cylinder plug 22 moves to the left, and the hydraulic rod 19 retracts and resets. In this process, the gas inside the threaded airbag 16 is transported to the injection head 24 through the injection pipe 13. The injection head 24 also has a built-in one-way valve to ensure the flow of gas. The injection head 24 sprays air at high speed to blow the heat dissipation fins 9 on the surface of the hydraulic cylinder 6, and the hydraulic cylinder 6 is used for air cooling and heat dissipation.

[0076] When the threaded airbag 16 is stretched, the fixed plate 2 15 will also be stretched. The water-cooled airbag 14 between the fixed plate 2 15 and the fixed plate 1 11 draws the coolant from the heat sink 9 through the cooling pipe 12 with a built-in one-way valve. As the cylinder plug 22 moves to the left, the strong magnetic plate 23 built into the cylinder plug 22 and the adjacent surfaces of the annular magnet 20 in the fixed plate 2 15 repel each other magnetically, thereby driving the fixed plate 2 15 to move leftward on the surface of the hydraulic rod 19. The water-cooling airbag 14 is stretched and the spring 21 is further pulled to accumulate elastic potential. Then, during the resetting process of the hydraulic rod 19, under the action of the spring 21, the water-cooling airbag 14 is reset and compressed, and the coolant is injected into the heat dissipation fins 9 through another cooling pipe 12 with a built-in one-way valve, so as to further realize the water-cooling circulation heat dissipation of the hydraulic cylinder 6. The two methods of air-cooling heat dissipation and water-cooling heat dissipation complement each other and greatly improve the heat dissipation effect of the hydraulic cylinder 6. The heat dissipation fins 9 are exposed to the outside for a long time, and dust and debris are easily attached between the heat dissipation fins 9. During the movement of the cylinder plug 22, the cleaning scraper 10 connected to the surface of the heat dissipation fins 9 by magnetic attraction moves to scrape and clean the surface of the heat dissipation fins 9, and the cleaned dust and debris are blown away from the surface of the heat dissipation fins 9 in conjunction with air-cooling heat dissipation.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tractor steering control method, characterized in that: The method comprises the following steps: Step 1: Steering angle feedback control: The steering angle is monitored in real time by an angle sensor installed on the steering cylinder. The data is fed back to the microcontroller through the control system to adjust the opening of the electronic control valve in the power steering gear and change the oil flow on both sides of the steering cylinder, thereby accurately controlling the steering angle. Step 2: Proportional control: Use proportional control algorithm to adjust the oil flow according to the deviation of the steering angle so that the steering angle reaches the target value quickly and smoothly. The core of proportional control is to maintain the difference in oil pressure on both sides of the cylinder and adjust the hydraulic flow and pressure; Step 3: Speed ​​compensation: The steering performance of the tractor varies at different speeds. By adding a speed compensation strategy to the control algorithm, the vehicle speed signal is added to avoid instability caused by over-fast steering at high speeds, while maintaining sufficient sensitivity and response speed at low speeds. Step 4: Load compensation: Depending on the load of the tractor, the output of the hydraulic system will also change. The load sensing control strategy is adopted to adjust the hydraulic flow and pressure in real time according to the load changes of the cylinder to ensure a stable steering angle and response speed; Step 5: Closed-loop control: Based on the steering angle feedback, the opening of the electronically controlled valve is adjusted through the PID control algorithm to accurately control the movement of the steering cylinder; Step 6: Fuzzy control: In complex working environments, such as different ground surfaces and changes in turning radius, a fuzzy control algorithm is used to determine changes in the steering angle using fuzzy logic rules and adjust the working state of the cylinder.

2. A tractor steering control method according to claim 1, characterized in that: In the step 1, steering angle feedback control, a steering angle sensor is used to feed back the steering angle θ in real time. The feedback signal is used to calculate the error and adjust the opening of the control valve. The hydraulic flow and pressure of the cylinder are adjusted according to the steering angle error Δθ to form a closed-loop control. In the control strategy, a PID controller is used to calculate the required flow and pressure of the cylinder. The formula is: Where: u(t) is the control output, i.e. the oil pressure or oil flow required by the steering cylinder, e(t) = θ target -θ(t) is the steering angle error, K p , K i , K d are proportional, integral and differential gains, θ target is the desired steering angle and θ(t) is the current steering angle.

3. A tractor steering control method according to claim 2, characterized in that: In the step 3, speed compensation, the control formula can introduce a speed compensation factor V: Where: f(v) is the speed compensation function, which is a linear or nonlinear function.

4. A tractor steering control method according to claim 3, characterized in that: Step 2: Proportional control, hydraulic flow Q and control signal v ctrl The relationship between them is: Q=βv ctrl ·ΔP Where: β is the flow gain of the valve, ΔP is the pressure difference across the valve, v ctrl It is the control signal, which is adjusted by PID control.

5. A tractor steering control method according to claim 4, characterized in that: The fourth step, load compensation, describes the hysteresis by introducing a dynamic model: i compensated (t)=θ(t)+γ·(θ(t)-θ prev (t)) Where: γ is the hysteresis compensation coefficient. θ prev (t) is the steering angle at the previous moment.

6. A tractor steering control device according to any one of claims 1 to 5, characterized in that: The invention comprises a hydraulic suspension body (1), wherein the left front axle (3) and the right front axle (4) are rotatably connected on both sides of the hydraulic suspension body (1), two groups of steering cylinders (2) are fixed on the front side of the hydraulic suspension body (1), the output shafts of the two groups of steering cylinders (2) are rotatably connected to the left front axle (3) and the right front axle (4) respectively for controlling the deflection of the left front axle (3) and the right front axle (4) at both ends of the hydraulic suspension body (1), and a power steering device (5) with a built-in electric control valve is also arranged on the rear side of the hydraulic suspension body (1), and the output end of the power steering device (5) is connected to the steering cylinder (2) through an oil pipe for oil transmission; The steering cylinder (2) comprises a hydraulic cylinder (6) and a hydraulic rod (19), one end of the hydraulic rod (19) extends into the hydraulic cylinder (6), one end of the hydraulic rod (19) located in the hydraulic cylinder (6) is connected and fixed with a cylinder plug (22) via a flange bolt, the outer wall of the cylinder plug (22) is in contact with the inner wall of the hydraulic cylinder (6), the outer symmetrical fixed connecting pipe of the hydraulic cylinder (6) comprises a joint 1 (7) and a joint 2 (8) connected to the oil pipe, the cylinder plug (22) is located between the joint 1 (7) and the joint 2 (8), and the movable distance of the cylinder plug (22) is between the joint 1 (7) and the joint 2 (8), and the end of the hydraulic rod (19) away from the cylinder plug (22) is fixedly connected with a collar (18) rotatably connected to the left front axle (3) and the right front axle (4).

7. A tractor steering control device according to claim 6, characterized in that: The outer ring of the hydraulic cylinder (6) is fixedly connected with a plurality of heat dissipation fins (9) with hollow structures at equal distances, and the outer movably connected with the heat dissipation fins (9) is connected with a cleaning scraper (10), the cleaning scraper (10) is designed with an arc structure and wrapped around the surface of the heat dissipation fins (9) and is vertically distributed with the heat dissipation fins (9), the cleaning scraper (10) is made of a magnetic metal material, and the inner part of the cylinder plug (22) is embedded with a strong magnetic plate (23), and the strong magnetic plate (23) is magnetically attracted to the cleaning scraper (10).

8. A tractor steering control device according to claim 7, characterized in that: The outside of the hydraulic rod (19) is respectively sleeved with a fixing plate three (17) and a fixing plate two (15); the fixing plate two (15) is movably connected to the hydraulic rod (19); the fixing plate three (17) is fixedly connected to the hydraulic rod (19); the outside of the hydraulic rod (19) located between the fixing plate three (17) and the fixing plate two (15) is sleeved with a threaded airbag (16); and the two ends of the threaded airbag (16) are respectively fixedly connected to the fixing plate three (17) and the fixing plate two (15).

9. A tractor steering control device according to claim 8, characterized in that: One end of the hydraulic rod (19) close to the threaded airbag (16) is fixedly connected to a fixing plate 1 (11); an injection pipe (13) is connected between the fixing plate 2 (15) and the fixing plate 1 (11); one end of the injection pipe (13) is connected to the threaded airbag (16); an injection head (24) is provided at equal intervals in a ring shape on one side of the fixing plate 1 (11) away from the injection pipe (13); the other end of the injection pipe (13) is connected to the injection head (24), and the injection head (24) is located between adjacent heat dissipation fins (9).

10. A tractor steering control device according to claim 9, characterized in that: The interior of the second fixing plate (15) is embedded with an annular magnet (20), a water-cooling airbag (14) is fixed between the second fixing plate (15) and the first fixing plate (11), and the water-cooling airbag (14) is sleeved on the outside of the hydraulic rod (19), the adjacent surfaces of the annular magnet (20) and the strong magnetic plate (23) magnetically repel each other, and a cooling pipe (12) is symmetrically fixedly connected to one side of the first fixing plate (11) close to the heat dissipation fin (9), one end of the cooling pipe (12) is connected to the water-cooling airbag (14), and the other end is connected to the heat dissipation fin (9), and the adjacent heat dissipation fins (9) are connected end to end, and a spring (21) is fixed inside the water-cooling airbag (14).

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