Automatic row alignment method and system for corn combine harvester

Abstract

The invention discloses an automatic row control method and system for a corn combine harvester. The method comprises the following steps: acquiring a real-time measurement value of a row angle sensor, recording an angle deviation value between the real-time measurement value and a preset initial angle value in a controller, and calculating a transverse deviation through the angle deviation value; judging whether the angle deviation value is greater than a preset deflection angle allowable error value or not; if yes, according to the angle deviation value and the transverse deviation, a rear wheel expected turning angle is calculated, and a steering instruction of the rear wheel is determined; if not, continuously recording the angle deviation value between the row-aligning angle sensor and the preset initial angle value in the controller in real time, and automatically aligning the electric steering wheel. The system comprises a row control module and a rear wheel turning angle detection device which are used for detecting the transverse deviation of crop deviation in real time and making corresponding adjustment. On the basis that it is guaranteed that the corn harvester conducts harvesting along corn crop rows, the automatic row alignment precision and the corn harvesting rate are improved.

Description

Technical Field

[0001] The invention belongs to the field of agricultural intelligent equipment, and relates to an automatic row alignment method and system for a corn combine harvester, which are mainly used for automatic row alignment control of a corn combine harvester. Technical Background

[0002] With the development of modern precision agriculture and smart agriculture, the level of agricultural mechanization has been significantly improved. As a key equipment in this process, combine harvesters have been widely used in corn harvesting operations. The automatic row alignment function is one of the key technologies for corn harvesting, which directly affects the efficiency and quality of harvesting operations. The traditional manual driving method requires the operator to continuously monitor the relative position between the harvester's header and the corn plants, which increases the labor intensity of the driver.

[0003] When the combine harvester harvests along the rows of corn crops, there are phenomena of misalignment and missing of corn crop rows, and the harvest quality of corn plants with non-straight row growth patterns is poor, which poses a challenge to mechanical automated harvesting. Corn row position detection methods are mainly divided into two types: non-contact detection and contact detection. Affected by factors such as working environment and cost-effectiveness, most corn combine harvesters on the market use contact detection, that is, detection is performed by a device equipped with a mechanical sensor, and fuzzy PID is used for control. However, due to the imperfect rule base of fuzzy control or the imperfect design of the rule base, the control effect is not ideal, resulting in poor row accuracy. Therefore, how to optimize the row alignment function of the corn combine harvester by improving the control algorithm to ensure the row alignment accuracy and harvesting quality of the corn combine harvester has become an urgent problem to be solved by the staff in this field. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an automatic row alignment method for a corn combine harvester to achieve an optimal path for the corn combine harvester during the automatic row alignment process.

[0005] A method for automatically aligning rows of a corn combine harvester, the corn combine harvester comprising a mechanical automatic row detection device for detecting crop deviation in real time, the mechanical automatic row detection device comprising a left row angle sensor device and a right row angle sensor device located on both sides of the front of the corn harvester, the left row angle sensor device comprising a left row angle sensor, the right row angle sensor device comprising a right row angle sensor, characterized in that the method comprises the following steps:

[0006] Step 1: during the automatic harvesting process of the corn harvester along the corn crop row, when the real-time angle signal detected by either the left row angle sensor or the right row angle sensor is collected, step 2 is executed;

[0007] Step 2: determining an angle deviation value according to the real-time angle signal and an initial angle value preset in the controller, and calculating a lateral deviation according to the angle deviation value;

[0008] Step 3: When it is determined that the angle deviation value is greater than the preset angle deviation allowable error, execute step 4; otherwise, execute step 6;

[0009] Step 4: calculating the rear wheel desired turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining the rear wheel steering instruction based on the rear wheel desired turning angle δ(n);

[0010] Step 5: Control the electric steering wheel of the corn combine harvester to rotate according to the rear wheel steering command; and return to execute step 2; wherein, in the controller for controlling the electric steering wheel steering, a weighted fitness function is designed to optimize the PSO algorithm for PID control, and the weighted fitness function can be expressed as: Where t is time, e(t) is the difference between the input and response of the optimized system, y1 is the instantaneous maximum deviation value, and y ∞ is the steady-state value, T s To adjust the time, A, B, and C are weights assigned by the system.

[0011] If the output result of step 3 is yes, return to step 2;

[0012] Step 6: The electric steering wheel of the corn combine harvester automatically returns to the center position;

[0013] Step 7: When the real-time angle signals detected by the left and right alignment angle sensors are collected simultaneously and the preset time duration is reached, the automatic alignment method is terminated.

[0014] The above-mentioned automatic row-aligning method for a corn combine harvester makes the control parameters in the controller converge to an optimal solution value through a weighted fitness function under the iterative calculation of the PSO algorithm to control the rotation of the electric steering wheel and realize the optimal path of the corn combine harvester during the automatic row-aligning process.

[0015] The mechanical automatic row detection device also includes a left detection rod and a right detection rod arranged on both sides of the front of the corn harvester. The left detection rod and the right detection rod are respectively connected to the left row angle sensor and the right row angle sensor. The lateral spacing distance between the left detection rod and the right detection rod is greater than or equal to 10 cm.

[0016] The calculation of δ(n) specifically includes:

[0017] S4.1: The left and right detection rods are respectively approximately fitted into a straight fitting detection rod, wherein the length of the straight rod portion is S1 and the length of the curved rod portion is S2, and the angles between the left and right detection rods and the fitting detection rod are respectively denoted as α, and the lateral deviation can be calculated:

[0018] Wherein, θ is the difference between the maximum real-time angle signal detected by the left-facing or right-facing angle sensor obtained in the controller and the preset initial angle value;

[0019] S4.2: Simplifying the corn combine harvester into a two-wheel steering model, the relationship between the desired rear wheel steering angle and the lateral deviation can be obtained:

[0020] Wherein, L is the rear wheelbase of the combine harvester, and γ is the vertical distance from the mechanical automatic row detection device to the front axle of the corn combine harvester.

[0021] There is a fixed transmission ratio between the electric steering wheel of the corn combine harvester and the rear wheel turning angle, and the determining of the rear wheel steering instruction based on the rear wheel expected turning angle δ(n) specifically includes:

[0022] S4.3: A steering command is determined according to the sign and value of the calculated rear wheel desired steering angle δ(n), wherein the steering command is used for the electric steering wheel to control the rear wheel steering for automatic steering;

[0023] The step of controlling the electric steering wheel rotation of the corn combine harvester according to the rear wheel steering instruction specifically includes:

[0024] S5.1: In the controller that controls the electric steering wheel, a weighted fitness function is designed to optimize the PSO algorithm for PID control so that the control parameter K in the controller p , K i , K d Under the iterative calculation of the PSO algorithm, the weighted fitness function converges to an optimal solution value to control the rotation of the electric steering wheel and realize the optimal path of the corn combine harvester during the automatic row alignment process.

[0025] The present invention also provides an automatic row alignment system for a corn combine harvester, comprising a row alignment control module and a rear wheel turning angle detection device.

[0026] The row alignment control module is used to determine a control signal for automatically aligning the rows of the corn combine harvester according to the detected crop deviation signal.

[0027] The rear wheel steering angle detection device is used to detect the angle value of the rear wheel steering in real time and feed it back to the controller, and ensure that when the angle deviation value determined by the real-time angle signal detected by either the left-facing angle sensor or the right-facing angle sensor and the initial angle preset in the controller is less than the allowable angle deviation error preset in the controller, the vehicle body can be smoothly returned to the center position.

[0028] The row control module includes a controller, a display screen connected to the controller by signals, an electric steering wheel and a mechanical automatic row detection device; wherein the mechanical automatic row detection device includes a left row angle sensor device and a right row angle sensor device installed on both sides of the front of the corn harvester, the left row angle sensor device and the right row angle sensor device respectively include a first angle sensor, a rotating shaft fixedly connected to the angle sensor, a detection rod assembly fixedly connected to the rotating shaft and a fixing plate fixedly connected to the detection rod assembly, the mechanical automatic row detection device is connected to the straw dividers on both sides of the front of the harvester through the fixing plates of the left row angle sensor device and the right row angle sensor device.

[0029] The rear wheel turning angle detection device includes a second angle sensor, an angle sensor fixing bracket connected to a first side of the second angle sensor, a connecting rod mechanism connected to a second side of the second angle sensor, and a connecting rod mechanism fixing bracket connected to the connecting rod mechanism and used to be connected to the rear wheel steering shaft of the corn combine harvester. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a working system diagram of the present invention installed on a corn combine harvester;

[0031] Figure 2 This is a diagram of a mechanical automatic line detection device;

[0032] Figure 3 It is a schematic diagram of the structure of the rear wheel angle detection device;

[0033] Figure 4 This is a flow chart of an automatic row alignment method for a corn combine harvester according to the present invention;

[0034] Figure 5 The flow chart of PID parameter optimization by PSO algorithm after introducing weighted fitness function;

[0035] Figure 6 This is the structure diagram of the PID controller optimized by the PSO algorithm after the weighted fitness function is introduced. DETAILED DESCRIPTION

[0036] 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.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 1 In the corn combine harvester shown, the row control module includes a display screen 101, an electric steering wheel 102, a controller 103 and a mechanical automatic row detection device 104.

[0039] like Figure 1 In the corn combine harvester shown in FIG. 1 , the mechanical automatic row detection device 104 has a structure as shown in FIG. Figure 2 As shown. The mechanical automatic row detection device comprises a left row angle sensor device and a right row angle sensor device installed on both sides of the front of the corn harvester, wherein the left row angle sensor device and the right row angle sensor device have the same composition structure, respectively comprising a first angle sensor 201, a rotating shaft 204 fixedly connected to the first angle sensor 201, a detection rod assembly fixedly connected to the rotating shaft 204, and a fixed plate 203 fixedly connected to the detection rod assembly, the mechanical automatic row detection device 104 is connected to the harvester divider through the fixed plate 203, when the detection rod 208 detects crop deviation, it drives the rotating shaft 204 to rotate a corresponding angle, and the first angle sensor 201 detects an angle signal, thereby detecting the lateral deviation of the crop deviation, wherein the detection rod assembly comprises a reset spring 205, a protective cover 206, a detection rod sleeve 207, and a detection rod 208.

[0040] Specifically, Figure 2 In the mechanical automatic row detection device shown, the mechanical automatic row detection device 104 is installed on the crop dividers on both sides of the same cutting path through the fixed plate 203 when in use. The detection rod 208 is fixedly connected to the rotating shaft 204 through the detection rod sleeve 207. The rotating shaft 204 is fixedly connected to the first angle sensor 201 through screws. The reset spring 205 is fixed to the through hole on the fixed plate 203 through the detection rod sleeve 207. The detection rod 208 generates a reset force under the action of the reset spring 205, and is reset to the initial measurement state through the opening angle limit of the protective cover 206. The bushing 202, the protective cover 206 and the fixed plate 203 are connected by bolts.

[0041] like Figure 1In the corn combine shown, the display is used to select manual mode or automatic row alignment mode and to display data from the angle sensor.

[0042] like Figure 1 In the corn combine harvester shown, the electric steering wheel is controlled by a controller to rotate.

[0043] like Figure 1 In the corn combine harvester shown, there is a fixed transmission ratio between the electric steering wheel and the rear wheel angle, which are connected by a steering mechanism. The electric steering wheel is controlled by a controller to achieve automatic row control.

[0044] like Figure 1 In the corn combine harvester shown in FIG. 1 , the rear wheel angle detection device 105 has a structure as shown in FIG. Figure 3 The rear wheel steering angle detection device 105 includes a second angle sensor 301, an angle sensor fixing frame 302 for fixing the second angle sensor 301, a connecting rod mechanism 303 connected to one end of the second angle sensor 301, and a connecting rod mechanism fixing frame 304 connected to the connecting rod mechanism 303 and used to fix the connecting rod mechanism 303 on the rear wheel steering shaft; specifically, one end of the connecting rod mechanism 303 is connected to the second angle sensor 301, the second angle sensor 301 is welded to the rear axle through the angle sensor fixing frame 302, and the other end is connected to the connecting rod mechanism The connecting rod mechanism fixing frame 303 is connected, and the connecting rod mechanism fixing frame 303 is welded to the steering shaft of the rear wheel; the upper surface of the angle sensor fixing frame 302 and the upper surface of the connecting rod mechanism fixing frame 304 are in the same horizontal plane to realize the synchronous rotation of the rear wheel and the angle sensor; the rear wheel steering angle detection device can detect and feedback the actual deflection angle of the rear wheel in real time, calculate the corresponding actual deflection distance according to the actual deflection angle, obtain the lateral error between the actual deflection distance and the lateral deviation, and ensure that the vehicle body can be smoothly returned to the center when the corn crop row is separated from the detection rod.

[0045] The working principle of automatic alignment mode is:

[0046] During the process of corn harvesting by a corn combine harvester, when the corn combine harvester deviates from the glutinous corn crop row due to uneven field ground and drift factors, or the corn crop row presents a non-linear growth pattern, the corn plant will touch one of the detection rods of the mechanical automatic row-aligning device and cause the detection rod to rotate. The detection rod drives the rotating shaft to rotate, and the rotating shaft directly transmits the angle to the angle sensor. The angle sensor transmits the rotation angle signal to the controller in the form of voltage. The controller obtains the angle deviation of the angle sensor, calculates the lateral deviation, determines the expected rear wheel angle and steering command, and then sends a steering command to the corn combine harvester to control the corn harvester to turn, so as to ensure that the corn harvester harvests along the corn row.

[0047] In one embodiment, in order to achieve precise control of automatic row alignment of a corn combine harvester, an automatic row alignment method for a corn combine harvester is provided. The corn combine harvester has a mechanical automatic row alignment detection device 104 for detecting crop deviation in real time. The mechanical automatic row alignment detection device 104 includes a left row alignment angle sensor device and a right row alignment angle sensor device located on both sides of the front of the corn harvester. The left row alignment angle sensor device includes a left row alignment angle sensor, i.e., a first angle sensor 201, and the right row alignment angle sensor device includes a right row alignment angle sensor, i.e., a first angle sensor 201. The specific steps include:

[0048] Step 1: during the automatic harvesting process of the corn harvester along the corn crop row, when a real-time angle signal detected by either the left row angle sensor or the right row angle sensor is collected, step 2 is executed;

[0049] Step 2: determining an angle deviation value according to the real-time angle signal and an initial angle value preset in the controller, and calculating a lateral deviation according to the angle deviation value;

[0050] Step 3: When it is determined that the angle deviation value is greater than the preset angle deviation allowable error, execute step 4; otherwise, execute step 6;

[0051] Step 4: calculating the rear wheel desired turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining the rear wheel steering instruction based on the rear wheel desired turning angle δ(n);

[0052] Step 5: Control the electric steering wheel of the corn combine harvester to rotate according to the rear wheel steering command; and return to execute step 2; wherein, in the controller for controlling the electric steering wheel steering, a weighted fitness function is designed to optimize the PSO algorithm for PID control, and the weighted fitness function can be expressed as: Where t is time, e(t) is the difference between the input and response of the optimized system, y1 is the instantaneous maximum deviation value, and y ∞ is the steady-state value, T s To adjust the time, A, B, and C are weights assigned by the system;

[0053] If the output result of step 3 is yes, return to step 2;

[0054] Step 6: The electric steering wheel of the corn combine harvester automatically returns to the center position;

[0055] Step 7: When the real-time angle signals detected by the left and right alignment angle sensors are collected simultaneously and the preset time duration is reached, the automatic alignment method is terminated.

[0056] The automatic row alignment method for a corn combine harvester is based on the control parameter K in the controller.p , K i , K d Under the iterative calculation of the PSO algorithm, the weighted fitness function converges to an optimal solution value to control the rotation of the electric steering wheel and realize the optimal path of the corn combine harvester during the automatic rowing process; PID control has large overshoot, slow response and low precision. The improved PSO-PID algorithm can optimize the PID control, fully considering the impact of overshoot and steady-state error on the system, which can not only reduce the overshoot, but also greatly improve the response time and control accuracy; at the same time, the improved PSO-PID algorithm can effectively suppress the overshoot of the system, has significant advantages in tracking performance, and has smaller errors, making the rotation of the electric steering wheel faster and more accurate.

[0057] The mechanical automatic row detection device also includes a left detection rod, namely, detection rod 208, and a right detection rod, namely, detection rod 208, which are arranged on both sides of the front of the corn harvester. The left detection rod and the right detection rod are respectively connected to the left row angle sensor and the right row angle sensor, and the lateral spacing distance between the left detection rod and the right detection rod is greater than or equal to 10 cm.

[0058] The calculation of δ(n) specifically includes:

[0059] S4.1: The left and right detection rods are respectively approximately fitted into a straight fitting detection rod, wherein the length of the straight rod portion is S1 and the length of the curved rod portion is S2, and the angles between the left and right detection rods and the fitting detection rod are respectively denoted as α, and the lateral deviation can be calculated:

[0060] Wherein, θ is the difference between the maximum real-time angle signal detected by the left-facing or right-facing angle sensor obtained in the controller and the preset initial angle value;

[0061] S4.2: Simplifying the corn combine harvester into a two-wheel steering model, the relationship between the desired rear wheel steering angle and the lateral deviation can be obtained:

[0062] Wherein, L is the rear wheelbase of the combine harvester, and γ is the vertical distance from the mechanical automatic row detection device to the front axle of the corn combine harvester.

[0063] There is a fixed transmission ratio between the electric steering wheel of the corn combine harvester and the rear wheel turning angle, and the determining of the rear wheel steering instruction based on the rear wheel expected turning angle δ(n) specifically includes:

[0064] S4.3: A steering command is determined based on the sign and value of the calculated desired rear wheel steering angle δ(n), and the steering command is used for the electric steering wheel to control the rear wheel steering for automatic steering.

[0065] In the controller for controlling the electric steering wheel steering, designing a weighted fitness function to optimize the PSO algorithm for PID control specifically includes:

[0066] The PSO algorithm can be specifically expressed as:

[0067]

[0068] Where: ω is the inertia weight, c1 and c2 are learning factors, r1 and r2 are random numbers in the range [0,1], t represents the number of iterations, and pBest i represents the individual best historical position of particle i, gBest i represents the global optimal position.

[0069] In the PSO algorithm, the optimal K p , K i , K d In the process of optimization, the inertia weight will affect the optimization ability. A larger inertia weight promotes global search, while a smaller inertia weight is conducive to local search. The present invention adopts the method of linear weight reduction to optimize the inertia weight, and its expression is:

[0070]

[0071] This expression can be used to balance the relationship between global search and local search.

[0072] In the iterative process of the PSO algorithm, the weighted fitness function is used to evaluate the optimal K p , K i , K d The weighted fitness function is a key component of the solution and can integrate performance indicators such as the adjustment time, overshoot and steady-state error in the controller.

[0073] According to the specific requirements of the automatic steering system, adjusting the system allocation weights A, B, and C of the weighted fitness function can optimize the influence of performance indicators such as adjustment time, overshoot, and steady-state error on the automatic steering system to achieve the best control effect.

[0074] like Figure 5 The flowchart of the PSO algorithm optimizing PID parameters after introducing the weighted fitness function is shown in the figure:

[0075] The PSO algorithm after weighted fitness function optimization is used to adjust the three parameters K of the controller. p , K i , K d Adjustment; First, in the three-dimensional search space, set a group of particles with a population size of 50 to simulate K p , Ki , K d In the optimization process, each particle starts with its own random position x i and random initial velocity v i , the fitness value is calculated by the defined weighted fitness function to judge the quality of the current position of the particle, and the optimal position of the individual particle and the global optimal position are recorded. According to equations (1) to (3), the particle continuously updates its position and speed in the solution space, and finally satisfies the iteration conditions, thereby outputting the optimal K p , K i , K d .

[0076] According to the actual deflection angle and actual deflection distance of the rear wheel obtained in real time by the rear wheel steering angle detection device, the lateral error between the lateral deviation of the mechanical automatic alignment detection device and the actual deflection distance is obtained, and the lateral error is fed back to the controller. The PSO algorithm optimized by the weighted fitness function is continuously updated and iterated to continuously update the optimal K p , K i , K d And output to the electric steering wheel.

[0077] like Figure 6 The figure shows the structure diagram of the PID controller optimized by the PSO algorithm after the weighted fitness function is introduced. The input signal of the module is the lateral deviation calculated according to the sensor deflection angle difference. The parameters of the PID controller are adjusted by the PSO algorithm after the weighted fitness function is introduced. The control object is the identified steering system function model. The output signal of the module is the offset distance of the corn combine harvester. The PSO-PID controller after the weighted fitness function optimization can ensure that the automatic row alignment system can quickly and stably complete the precise row alignment operation.

[0078] Compared with the prior art, the present invention provides a method and system for automatically aligning rows of a corn combine harvester, which enables the corn combine harvester to more accurately control the rotation and return of the electric steering wheel, thereby improving the accuracy of automatic row alignment. The advantages and beneficial effects of the present invention are as follows:

[0079] The automatic row alignment method of the present invention collects angle data in real time through the left and right row alignment angle sensors in the automatic row alignment device, finds the current optimal Kp, Ki, and Kd parameters in real time through the improved PSO-PID algorithm, and controls the steering wheel rotation to obtain the best row alignment accuracy of the corn combine harvester.

[0080] The present invention uses a line control module to intuitively display the initial angle value of the sensor, the real-time angle signal of the sensor and the lateral deviation on a display screen in the cab, making it convenient for the driver to observe and control.

[0081] The present invention includes a rear wheel turning angle detection transposition. Based on a two-wheel steering model, the lateral deviation can be detected in real time and accurately through the left and right row angle sensors in the mechanical automatic row detection device. When the left and right row angle sensors are separated from the corn detection rod, the electric steering wheel is controlled to return to the center through the second angle sensor, thereby improving the electric steering wheel return accuracy.

[0082] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0083] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for automatically aligning rows of a corn combine harvester, the corn combine harvester comprising a mechanical automatic row alignment detection device for detecting crop deviation in real time, the mechanical automatic row alignment detection device comprising a left row alignment angle sensor device and a right row alignment angle sensor device located on both sides of the front of the corn harvester, the left row alignment angle sensor device comprising a left row alignment angle sensor, the right row alignment angle sensor device comprising a right row alignment angle sensor, characterized in that: The following steps are involved: Step 1: during the automatic harvesting process of the corn harvester along the corn crop row, when the real-time angle signal detected by either the left row angle sensor or the right row angle sensor is collected, step 2 is executed; Step 2: determining an angle deviation value according to the real-time angle signal and an initial angle value preset in the controller, and calculating a lateral deviation according to the angle deviation value; Step 3: When it is determined that the angle deviation value is greater than the preset angle deviation allowable error, execute step 4; otherwise, execute step 6; Step 4: calculating the rear wheel desired turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining the rear wheel steering instruction based on the rear wheel desired turning angle δ(n); Step 5: Control the electric steering wheel of the corn combine harvester to rotate according to the rear wheel steering command; and return to execute step 2; wherein, in the controller for controlling the electric steering wheel steering, a weighted fitness function is designed to optimize the PSO algorithm for PID control, and the weighted fitness function can be expressed as: Where t is time, e(t) is the difference between the input and response of the optimized system, y1 is the instantaneous maximum deviation value, and y ∞ is the steady-state value, T s To adjust the time, A, B, and C are weights assigned by the system; Step 6: The electric steering wheel of the corn combine harvester automatically returns to the center position; Step 7: When the real-time angle signals detected by the left and right alignment angle sensors are collected simultaneously and the preset time duration is reached, the automatic alignment method is terminated.

2. The automatic row alignment method for a corn combine harvester according to claim 1, characterized in that: The mechanical automatic row detection device also includes a left detection rod and a right detection rod arranged on both sides of the front of the corn harvester. The left detection rod and the right detection rod are respectively connected to the left row angle sensor and the right row angle sensor. The lateral spacing distance between the left detection rod and the right detection rod is greater than or equal to 10 cm.

3. The automatic row alignment method for a corn combine harvester according to claim 2, wherein the left detection rod and the right detection rod have a straight rod part and a curved rod part, characterized in that: The calculation of δ(n) specifically includes: S4.1: The left and right detection rods are respectively approximately fitted into a straight fitting detection rod, wherein the length of the straight rod portion is S1 and the length of the curved rod portion is S2, and the angles between the left and right detection rods and the fitting detection rod are respectively denoted as α, and the lateral deviation can be calculated: Wherein, θ is the difference between the maximum real-time angle signal detected by the left-facing or right-facing angle sensor obtained in the controller and the preset initial angle value; S4.2: Simplifying the corn combine harvester into a two-wheel steering model, the relationship between the desired rear wheel steering angle and the lateral deviation can be obtained: Wherein, L is the rear wheelbase of the combine harvester, and γ is the vertical distance from the mechanical automatic row detection device to the front axle of the corn combine harvester.

4. The automatic row alignment method for a corn combine harvester according to claim 1, wherein there is a fixed transmission ratio between the electric steering wheel and the rear wheel angle of the corn combine harvester, characterized in that: The determining of the rear wheel steering command based on the rear wheel expected turning angle δ(n) specifically includes: S4.3: A steering command is determined based on the sign and value of the calculated desired rear wheel steering angle δ(n), and the steering command is used for the electric steering wheel to control the rear wheel steering for automatic steering.

5. An automatic row alignment system for a corn combine harvester, characterized in that: It includes a row control module and a rear wheel turning angle detection device. The row control module is used to determine the control signal for automatically controlling the corn combine harvester in accordance with the detected crop deviation signal; the rear wheel turning angle detection device is used to detect the angle value of the rear wheel steering in real time and feed it back to the controller, and ensure that when the angle deviation value determined by the real-time angle signal detected by either the left row angle sensor or the right row angle sensor and the initial angle preset in the controller is less than the allowable deviation error preset in the controller, the vehicle body can be smoothly returned to the center.

6. The automatic row alignment system for a corn combine harvester according to claim 5, characterized in that: The row control module includes a controller, a display screen connected to the controller by signals, an electric steering wheel and a mechanical automatic row detection device; wherein the mechanical automatic row detection device includes a left row angle sensor device and a right row angle sensor device installed on both sides of the front of the corn harvester, the left row angle sensor device and the right row angle sensor device respectively include a first angle sensor, a rotating shaft fixedly connected to the angle sensor, a detection rod assembly fixedly connected to the rotating shaft and a fixing plate fixedly connected to the detection rod assembly, the mechanical automatic row detection device is connected to the straw dividers on both sides of the front of the harvester through the fixing plates of the left row angle sensor device and the right row angle sensor device.

7. The automatic row alignment system for a corn combine harvester according to claim 5, characterized in that: The rear wheel turning angle detection device includes a second angle sensor, an angle sensor fixing bracket connected to a first side of the second angle sensor, a connecting rod mechanism connected to a second side of the second angle sensor, and a connecting rod mechanism fixing bracket connected to the connecting rod mechanism and used to be connected to the rear wheel steering shaft of the corn combine harvester.

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