Automatic row alignment method and system for corn combine harvester

Abstract

The present invention discloses a method and system for automatic row alignment of a corn combine harvester. The method comprises: obtaining the real-time measurement value of the row angle sensor and recording the angle deviation value from the initial angle value preset in the controller, and calculating the lateral deviation based on the angle deviation value; judging whether the angle deviation value is greater than the preset allowable error value of the deflection angle; if so, calculating the expected rear wheel turning angle based on the angle deviation value and the lateral deviation and determining the steering instruction of the rear wheel; if not, continuing to record the angle deviation value between the row angle sensor and the initial angle value preset in the controller in real time, and the electric steering wheel automatically returns to the center. The system comprises: a row control module and a rear wheel turning angle detection device, which are used to detect the lateral deviation of the crop offset in real time and make corresponding adjustments. The present invention improves the automatic row alignment accuracy and corn harvest rate on the basis of ensuring that the corn harvester harvests along the corn crop row.

Description

Technical Field

[0001] The present 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 is mainly used for automatic row alignment control of a corn combine harvester. Technical Background

[0002] With the development of modern precision agriculture and smart farming, the level of agricultural mechanization has significantly increased. Combine harvesters, a key piece of equipment in this process, have become widely used for harvesting corn fields. Automatic row alignment is a key technology for corn harvesting, directly impacting the efficiency and quality of harvesting operations. Traditional manual operation requires the operator to constantly monitor the relative position of the harvester's header and the corn plants, increasing the driver's workload.

[0003] When a combine harvester harvests corn rows, it can sometimes miss or miss rows, and the harvest quality is poor for corn plants with non-straight growth patterns, posing a challenge to automated harvesting. Corn row position detection methods are primarily categorized as non-contact and contact detection. Due to factors such as the working environment and cost-effectiveness, most corn combine harvesters on the market use contact detection, which involves detecting with a device equipped with a mechanical sensor and controlling using a fuzzy PID control method. However, due to incomplete or imperfect rule bases for fuzzy control, the control effect is suboptimal, resulting in poor row alignment accuracy. Therefore, optimizing the row alignment function of a corn combine harvester by improving the control algorithm to ensure row alignment accuracy and harvest quality has become an urgent issue for researchers in this field. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for automatic row alignment of a corn combine harvester, so as 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 including a mechanical automatic row alignment detection device for detecting crop deviation in real time, the mechanical automatic row alignment detection device including 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 including a left row alignment angle sensor, and the right row alignment angle sensor device including a right row alignment 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 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;

[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 a desired rear wheel turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining a rear wheel steering command based on the desired rear wheel turning angle δ(n);

[0010] Step 5: Control the electric steering wheel of the corn combine harvester according to the rear wheel steering command; and return to 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 lane angle sensor and the right lane angle sensor are collected simultaneously and the preset time length is reached, the automatic lane alignment method is terminated.

[0014] The above-mentioned automatic row-aligning method for a corn combine harvester enables the control parameters in the controller to converge to an optimal solution value through a weighted fitness function under the iterative calculation of the PSO algorithm, so as 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: Approximately fit the left and right probing rods into a straight fitting probing rod, where the length of the straight rod portion is S1 and the length of the curved rod portion is S2. The angle between the left and right probing rods and the fitting probing rod is denoted as α. The lateral deviation can be calculated as:

[0018] Wherein, θ is the difference between the maximum real-time angle signal detected by the left or right row 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 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 and the rear wheel turning angle of the corn combine harvester, and determining 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 based on the sign and value of the calculated desired rear wheel steering angle δ(n). The steering command is used by the electric steering wheel to control rear wheel steering for automatic lane control.

[0023] The controlling the rotation of the electric steering wheel 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, design a weighted fitness function to optimize the PSO algorithm for PID control so that the control parameter K in the controller is 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 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 rear wheel steering angle value 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 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 respectively connected to the controller by signal, 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 fixed 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 fixed plates of the left row angle sensor device and the right row angle sensor device.

[0029] The rear wheel 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 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 Flowchart of PID parameter optimization using 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 clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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 alignment control module includes a display screen 101 , an electric steering wheel 102 , a controller 103 , and a mechanical automatic row alignment detection device 104 .

[0039] like Figure 1 In the corn combine harvester shown in FIG. 1 , the mechanical automatic row detection device 104 is structured as follows: Figure 2 As shown. The mechanical automatic row alignment detection device includes a left row alignment angle sensor device and a right row alignment angle sensor device installed on both sides of the front of the corn harvester. The left row alignment angle sensor device and the right row alignment angle sensor device have the same structure, respectively including 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 alignment detection device 104 is connected to the harvester's crop divider via 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. The detection rod assembly includes a return spring 205, a protective cover 206, a detection rod sleeve 207, and a detection rod 208.

[0040] Specifically, if Figure 2 In the mechanical automatic row detection device shown, the mechanical automatic row detection device 104 is installed on the 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 a screw. 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 rowing.

[0044] like Figure 1 In the corn combine harvester shown in FIG. 1 , the rear wheel angle detection device 105 is structured as follows: Figure 3 The rear wheel steering angle detection device 105 includes a second angle sensor 301, an angle sensor fixing bracket 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 bracket 304 connected to the connecting rod mechanism 303 and used to fix the connecting rod mechanism 303 to 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 bracket 302, and the other end is connected to the connecting rod mechanism The connecting rod mechanism fixing frame 303 is connected to the connecting rod mechanism fixing frame 303, 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 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, and obtain the lateral error between the actual deflection distance and the lateral deviation, so as to 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 line alignment mode is:

[0046] During the process of harvesting corn with 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 shows a non-linear growth pattern, the corn plant will touch one of the detection rods of the mechanical automatic row-aligning device, causing the detection rod to rotate. The detection rod drives the rotating shaft to rotate, and the rotating shaft then 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, a method for automatic row alignment of a corn combine harvester is provided. The corn combine harvester includes 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 a desired rear wheel turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining a rear wheel steering command based on the desired rear wheel turning angle δ(n);

[0052] Step 5: Control the electric steering wheel of the corn combine harvester according to the rear wheel steering command; and return to 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 lane angle sensor and the right lane angle sensor are collected simultaneously and the preset time length is reached, the automatic lane 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 not only reduces the overshoot, but also greatly improves the response time and control accuracy; at the same time, the improved PSO-PID algorithm can effectively suppress the system overshoot, 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 the detection rod 208, and a right detection rod, namely the 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. 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: Approximately fit the left and right probing rods into a straight fitting probing rod, where the length of the straight rod portion is S1 and the length of the curved rod portion is S2. The angle between the left and right probing rods and the fitting probing rod is denoted as α. The lateral deviation can be calculated as:

[0060] Wherein, θ is the difference between the maximum real-time angle signal detected by the left or right row 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 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 and the rear wheel turning angle of the corn combine harvester, and determining 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). The steering command is used by the electric steering wheel to control rear wheel steering for automatic lane control.

[0065] In the controller for controlling the electric steering wheel, 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 Indicates the individual historical optimal 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 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 adjustment time, overshoot and steady-state error in the controller.

[0073] According to the specific requirements of the automatic steering system, the system allocation weights A, B, and C of the weighted fitness function are adjusted to optimize the impact 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 for 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 particle swarms 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 formula (1) to formula (3), the particle continuously updates its position and speed in the solution space, and finally satisfies the iteration condition, 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 angle detection device, the lateral error between the lateral deviation of the mechanical automatic line 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 diagram shows the structure of a PID controller optimized by the PSO algorithm using a weighted fitness function. The module's input signal is the lateral deviation calculated from the sensor's deflection angle difference. The PSO algorithm, optimized with the weighted fitness function, is used to tune the PID controller's parameters. The control object is the identified steering system function model. The module's output signal is the offset distance of the corn combine harvester. This optimized PSO-PID controller ensures that the automatic row alignment system can quickly and stably complete precise row alignment operations.

[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 uses the left and right row alignment angle sensors in the automatic row alignment device to collect angle data in real time, uses the improved PSO-PID algorithm to find the current optimal Kp, Ki, and Kd parameters in real time, 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 sensor's initial angle value, the sensor's real-time angle signal, 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 angle detection transposition. Based on the two-wheel steering model, the lateral deviation can be accurately detected in real time by the left and right alignment angle sensors in the mechanical automatic alignment detection device. When the left and right alignment angle sensors are separated from the corn detection stalk, the electric steering wheel is controlled to return to the center position by 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] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed 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, and 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 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; 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 a desired rear wheel turning angle δ(n) according to the angle deviation value and the lateral deviation, and determining a rear wheel steering command based on the desired rear wheel turning angle δ(n); Step 5: Control the electric steering wheel of the corn combine harvester according to the rear wheel steering command; and return to 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 lane angle sensor and the right lane angle sensor are collected simultaneously and the preset time length is reached, the automatic lane 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 portion and a curved rod portion, characterized in that: The calculation of δ(n) specifically includes: S4.1: Approximately fit the left and right probing rods into a straight fitting probing rod, where the length of the straight rod portion is S1 and the length of the curved rod portion is S2. The angle between the left and right probing rods and the fitting probing rod is denoted as α. The lateral deviation can be calculated as: Wherein, θ is the difference between the maximum real-time angle signal detected by the left or right row 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 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 a fixed transmission ratio exists 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 instruction 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). The steering command is used by the electric steering wheel to control rear wheel steering for automatic lane control.

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