Agricultural machine and automatic driving control method and system thereof

Abstract

The invention discloses an agricultural machine and an automatic driving control method and system thereof. The automatic driving control method comprises the following steps: acquiring a theoretical target steering angle and a theoretical current steering angle of the agricultural machine; calculating an understeering coefficient of the agricultural machine in the current driving process; calculating a current actual target steering angle of the agricultural machine according to the theoretical target steering angle and the steering insufficiency coefficient; calculating an actual current steering angle of the agricultural machine according to the theoretical current steering angle and the steering insufficiency coefficient; acquiring a target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle; and controlling the agricultural machine to move according to the target steering angle of the electric steering wheel. According to the method, the transverse control parameters can be dynamically adjusted according to the current insufficient steering state of the agricultural machine, and a better control effect is achieved under the conditions that the ground is uneven in dryness, humidity and hardness, the vehicle load change is large and the steering performance is unstable.

Description

Technical Field

[0001] The present application belongs to the field of autonomous driving technology, and specifically relates to an agricultural machine and an autonomous driving control method and system thereof. Background Art

[0002] The current lateral control scheme of navigation equipment for agricultural machinery is limited by hardware equipment and often cannot obtain the current slip rate and understeer of agricultural machinery. Therefore, when calculating the target turning angle of the steering wheel of agricultural machinery, the real-time changing slip rate and understeer are often not taken into account. In addition, when calculating the target angle of steering wheel rotation, a fixed steering ratio is also used for calculation. This method works well when the tires have good grip. However, when the working plot is unevenly wet, soft and hard, and the load of the machine changes greatly, the steering of agricultural machinery will become very unstable, that is, understeer problems will often occur, and the understeer situation changes very quickly. In this case, the steering control of agricultural machinery often fails to achieve the desired effect, and then there will be problems with large trajectory tracking errors. Summary of the invention

[0003] The purpose of the present application is to provide an agricultural machinery and its automatic driving control method and system, so as to solve the technical problem that the steering of the agricultural machinery is unstable and cannot achieve the expected steering when the working land is unevenly hard and the vehicle load is heavy.

[0004] In order to achieve the above-mentioned object, the present application provides, on one hand, an automatic driving control method for agricultural machinery, wherein the agricultural machinery includes an electric steering wheel, and the automatic driving control method includes the steps of:

[0005] Obtaining a theoretical target steering angle and a theoretical current steering angle of the agricultural machinery;

[0006] calculating an understeering coefficient of the agricultural machinery during a current driving process;

[0007] Calculating a current actual target steering angle of the agricultural machinery according to the theoretical target steering angle and the understeering coefficient;

[0008] Calculating an actual current steering angle of the agricultural machinery according to the theoretical current steering angle and the understeering coefficient;

[0009] Acquire a target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle;

[0010] The agricultural machinery is controlled to move according to the target steering angle of the electric steering wheel.

[0011] In some embodiments, the step of obtaining the theoretical target steering angle of the agricultural machinery includes:

[0012] Obtaining current location information of the agricultural machinery;

[0013] Calculating the deviation between the current position information of the agricultural machinery and the relative position information of the navigation line;

[0014] The theoretical target steering angle of the agricultural machinery is obtained according to the deviation between the current position information and the relative position information.

[0015] In some embodiments, the theoretical current steering angle is obtained by the following calculation formula:

[0016] δ=arctan(L·w / v)

[0017] Wherein, δ is the theoretical current steering angle, v is the driving linear speed of the agricultural machinery, L is the wheelbase of the agricultural machinery, and w is the yaw angular velocity of the agricultural machinery during driving.

[0018] In some embodiments, the step of calculating the understeering coefficient of the agricultural machinery during the current driving process includes:

[0019] Obtaining a dynamic steering ratio and a fixed steering ratio of the electric steering wheel;

[0020] An understeering coefficient of the agricultural machinery within a preset time range is calculated according to a ratio of the dynamic steering ratio of the electric steering wheel to the fixed steering ratio.

[0021] In some embodiments, the step of calculating the dynamic steering ratio includes:

[0022] Acquire a set of operating steering angles and a set of electric steering wheel angle data of the agricultural machinery within a preset time range;

[0023] Calculating a change value of an operating steering angle of the agricultural machinery according to the operating steering angle set;

[0024] Calculating the effective rotation amount of the electric steering wheel according to the electric steering wheel angle data set;

[0025] A dynamic steering ratio of the electric steering wheel is obtained according to the effective rotation amount of the electric steering wheel and the operational steering angle change value.

[0026] In some implementations, the understeer coefficient is obtained by the following calculation formula:

[0027] k=steer_ratio_dynamic / steer_ratio

[0028] Wherein, k is the understeering coefficient, steer_ratio is the fixed steering ratio of the electric steering wheel, and steer_ratio_dynamic is the dynamic steering ratio of the electric steering wheel.

[0029] In some implementations, the step of acquiring the target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle comprises:

[0030] Obtaining a difference between the actual current steering angle and the actual target steering angle;

[0031] Obtaining a fixed steering ratio of the electric steering wheel;

[0032] A target steering angle of the electric steering wheel is calculated based on the difference and the fixed steering ratio.

[0033] A second aspect of the present application provides an automatic driving control system for agricultural machinery, which adopts the automatic driving control method as described above, and the automatic driving control system includes:

[0034] A navigation receiver, used to obtain the current position information of the agricultural machinery in real time and calculate the relative position deviation of the navigation line;

[0035] An electric steering wheel, used for transmitting the steering angle of the agricultural machinery in real time;

[0036] a calculation module, electrically connected to the electric steering wheel and the navigation receiver, the calculation module being used to calculate an understeering coefficient of the electric steering wheel according to information fed back by the navigation receiver and the electric steering wheel;

[0037] A control module is electrically connected to the calculation module, and the control module adjusts the steering dynamics of the agricultural machinery in real time according to the understeering coefficient.

[0038] In some embodiments, the automatic driving control system further includes a display module electrically connected to the control module, and the display module is used to display current steering dynamic information of the agricultural machinery.

[0039] A third aspect of the present application provides an agricultural machine, comprising the automatic driving control system as described above.

[0040] Through the above technical scheme, during the automatic driving of the vehicle, the theoretical target steering angle and the theoretical current steering angle of the agricultural machinery are obtained in real time; the understeering coefficient of the agricultural machinery during the current driving process is calculated; the actual target steering angle of the agricultural machinery is calculated according to the theoretical target steering angle and the understeering coefficient; the actual current steering angle of the agricultural machinery is calculated according to the theoretical current steering angle and the understeering coefficient; the target steering angle of the electric steering wheel is obtained according to the actual current steering angle and the actual target steering angle; the agricultural machinery is controlled to move according to the target steering angle of the electric steering wheel. By introducing the understeering coefficient, the present application can dynamically adjust the steering dynamics of the vehicle according to the current understeering state of the agricultural machinery, thereby achieving better control effects when the ground is unevenly dry, wet, soft and hard, the vehicle load changes greatly, and the steering performance is unstable.

[0041] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without creative work. In the drawings:

[0043] Figure 1 A schematic diagram of the flow chart of the automatic driving control method for agricultural machinery of the present application;

[0044] Figure 2 This is a schematic diagram of the module connections of the automatic driving control system for agricultural machinery of the present application. DETAILED DESCRIPTION

[0045] The specific implementation of the present application is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present application, and is not used to limit the present application.

[0046] The following describes the agricultural machinery and its automatic driving control method and system according to the present application with reference to the accompanying drawings.

[0047] like Figure 1 As shown, the present application provides an automatic driving control method for agricultural machinery, the agricultural machinery includes an electric steering wheel, and the automatic driving control method includes the steps of:

[0048] S10: Obtaining a theoretical target steering angle and a theoretical current steering angle of the agricultural machinery;

[0049] S20: calculating the understeering coefficient of the agricultural machinery during the current driving process;

[0050] S30: Calculating the current actual target steering angle of the agricultural machinery according to the theoretical target steering angle and the understeering coefficient;

[0051] S40: Calculating the actual current steering angle of the agricultural machinery according to the theoretical current steering angle and the understeering coefficient;

[0052] S50: Obtaining a target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle;

[0053] S60: Controlling the movement of agricultural machinery according to a target steering angle of an electric steering wheel.

[0054] Due to uneven wetness, softness and hardness of the working land and large changes in the load of the machine, the steering of the vehicle will become very unstable, making it impossible to perform expected control during the steering process, which in turn causes the vehicle's driving trajectory to deviate from the target path. In the present invention, by introducing an understeering coefficient and dynamically adjusting the steering of the vehicle in real time according to the understeering coefficient, it can adapt to the automatic driving control scenario where the vehicle slips and understeering conditions change rapidly, and achieve the purpose of improving the trajectory tracking accuracy.

[0055] Specifically, in the process of automatic driving, the theoretical target steering angle and the theoretical current steering angle of the agricultural machinery are first obtained, wherein the theoretical target steering angle is calculated based on the navigation receiver and the vehicle position information, and the theoretical current steering angle is calculated based on the vehicle's kinematic model, the vehicle's angular velocity, linear velocity, wheelbase information, etc.; then, during the vehicle's driving process, the current understeering coefficient is calculated according to the understeering calculation method; the current actual target steering angle of the agricultural machinery can be obtained by multiplying the theoretical target steering angle and the understeering coefficient; the actual current steering angle of the agricultural machinery can be obtained by multiplying the theoretical current steering angle and the understeering coefficient. Further, by comparing the actual target steering angle and the actual current steering angle, when there is a difference between the actual target steering angle and the actual current steering angle, the target steering angle of the electric steering wheel can be obtained according to the product of the difference and the fixed steering ratio of the electric steering wheel, and the motor is controlled to rotate the target steering angle according to the target steering angle, thereby completing the lateral steering motion control of the vehicle.

[0056] In some embodiments, the step of obtaining the theoretical target steering angle of the agricultural machinery includes:

[0057] Get the current location information of agricultural machinery;

[0058] Calculate the deviation between the current position information of the agricultural machinery and the relative position information of the navigation line;

[0059] The theoretical target steering angle of the agricultural machinery is obtained according to the deviation between the current position information and the relative position information.

[0060] In this embodiment, the theoretical target steering angle is mainly obtained by adopting a pure tracking control algorithm. It should be noted that the pure tracking control algorithm is based on the current position and speed of the vehicle, and finds a preview point at a certain distance ahead on the planned trajectory (that is, the navigation line), and then uses the rear axle center as a reference to find the front wheel steering angle that allows the vehicle to move to the preview point, which is the theoretical target steering angle in this embodiment.

[0061] In some implementations, the theoretical current steering angle can be obtained by the following calculation formula:

[0062] δ=arctan(L·w / v)

[0063] Among them, δ is the theoretical current steering angle, v is the driving linear speed of the agricultural machinery, L is the wheelbase of the agricultural machinery, and w is the yaw angular velocity of the agricultural machinery during driving.

[0064] When calculating the theoretical current steering angle, first use the following bicycle model vehicle kinematics and physical formulas: R = L / tanδ, w = v / R

[0065] Among them, v is the vehicle linear velocity, L is the vehicle wheelbase, and w is the vehicle yaw angular velocity. It can be obtained:

[0066] δ=arctan(L·w / v)

[0067] In this formula, L is a fixed parameter of the agricultural machinery body, and the yaw angular velocity w and the vehicle linear velocity v can be obtained through the navigation receiver. Therefore, the real-time theoretical current steering angle δ of the vehicle can be calculated according to the above formula.

[0068] In some embodiments, the step of calculating the understeering coefficient of the agricultural machinery during the current driving process includes:

[0069] Get dynamic steering ratio and fixed steering ratio of electric steering wheel;

[0070] An understeering coefficient of the agricultural machinery within a preset time range is calculated according to a ratio of a dynamic steering ratio and a fixed steering ratio of the electric steering wheel.

[0071] When the vehicle has good grip, the steering wheel turns at a certain angle, which corresponds to the vehicle running at a certain turning radius. In the abstract bicycle model with front-wheel steering, this relationship can be expressed as follows: R = wheelbase / tanδ, where R is the turning radius of the rear axle center, wheelbase is the vehicle wheelbase, and δ is the steering angle of the front wheel. However, when the ground grip is insufficient, resulting in understeering of the vehicle, the vehicle will not be able to achieve the steering effect when the grip is good, and the following situation will occur: R>wheelbase / tanδ, and when the ground grip changes greatly, the same front wheel steering angle δ will cause the vehicle to run at various turning radii R, resulting in a very unstable vehicle. The purpose of the control algorithm to calculate the target front wheel steering angle is actually to make the vehicle run at a certain turning radius. When understeering occurs and the understeering situation changes dramatically, the corresponding relationship between the front wheel steering angle and the turning radius will also change. In order to measure this relationship, we need to define an understeering coefficient k. Assuming that in the current actual situation, the turning radius of the vehicle is R, the vehicle running steering angle calculated by R = wheelbase / tanδ is δ0. At this time, the actual front wheel steering angle is δ1, and the understeer coefficient is: k = δ1 / δ0. Therefore, it can be seen that when the vehicle has good grip, k = 1; but when the front wheel slips and understeers, k is greater than 1; when the vehicle is completely unable to turn, if the actual front wheel steering angle is not 0, then k = ∞.

[0072] However, when actually calculating the understeering coefficient, only the data of δ0 can be obtained, while δ1 cannot be obtained. Therefore, when calculating the understeering coefficient, the calculation can be performed based on the data of the navigation receiver and the electric steering wheel. Specifically, when calculating the understeering coefficient, the dynamic steering ratio and the fixed steering ratio of the electric steering wheel are first obtained. The understeering coefficient of the electric steering wheel can be obtained according to the ratio of the dynamic steering ratio and the fixed steering ratio of the electric steering wheel. This control process can calculate the understeering coefficient without installing a steering wheel angle sensor. Of course, in other embodiments, a steering wheel angle sensor can also be installed on the vehicle, so that the actual steering angle of the vehicle can be directly obtained, and then the understeering coefficient can be directly calculated based on the running steering angle of the vehicle, and subsequent control can be performed. Or if the slip rate on the vehicle wheel can be directly obtained, a similar control effect can be achieved.

[0073] In some embodiments, the step of calculating the dynamic steering ratio includes:

[0074] Obtaining a set of operating steering angles and a set of electric steering wheel angle data of the agricultural machinery within a preset time range;

[0075] Calculating a change value of an operating steering angle of the agricultural machinery according to an operating steering angle set;

[0076] Calculate the effective rotation amount of the electric steering wheel according to the electric steering wheel angle data set;

[0077] The dynamic steering ratio of the electric steering wheel is obtained according to the effective rotation amount of the electric steering wheel and the running steering angle change value.

[0078] When calculating the dynamic steering ratio, it is first necessary to obtain the operating steering angle set and the electric steering wheel angle data set of the agricultural machinery in the previous time period, wherein the time period can be a relatively short time period, and the interval time of the time period can be set according to actual needs. The operating steering angle set is the operating angle data set composed of multiple time points selected within a period of time. Similarly, the electric steering wheel angle data set is the electric steering wheel angle values ​​selected at the same time point interval within a period of time, and then the electric steering wheel angle data set composed of multiple electric steering wheel angle values. Secondly, the rotation amount of the electric steering wheel outside the dead zone is obtained through the electric steering wheel angle data set, which is the effective rotation amount. Finally, the dynamic steering ratio of the electric steering wheel is obtained according to the ratio between the effective rotation amount of the electric steering wheel and the change value of the operating steering angle. In this embodiment, the dynamic steering ratio is calculated by the effective rotation amount of the electric steering wheel and the change value of the operating steering angle, and the calculation result is more accurate, thereby achieving more accurate steering control.

[0079] In some implementations, the fixed steering ratio may be obtained as follows:

[0080] First, at a first time point, a first angle of an electric steering wheel in the agricultural machinery and a first operating steering angle of the front wheels corresponding to the first angle are obtained, and then at a second time point, a second angle of the electric steering wheel in the agricultural machinery and a second operating steering angle of the front wheels corresponding to the second angle are obtained; the difference between the first angle and the second angle of the electric steering wheel is calculated as the steering wheel angle difference, and the difference between the first operating steering angle and the second operating steering angle of the front wheels within the range of the two time points is calculated as the operating steering angle difference, and the fixed steering ratio of the agricultural machinery can be obtained by the ratio between the steering wheel angle difference of the electric steering wheel and the operating steering angle difference of the front wheels.

[0081] In this embodiment, when calculating the fixed steering ratio, the fixed steering ratio of the electric steering wheel can be obtained by obtaining the angle change value of the electric steering wheel and the running steering angle change value according to the method described above, and according to the ratio of the two.

[0082] When obtaining the dynamic steering ratio and the fixed steering ratio, it is done directly through the calculation module of the control system. The whole process is more automated and does not require human intervention. It can make the steering adjustment more precise, thereby ensuring that the vehicle can travel according to the preset trajectory.

[0083] In some implementations, the understeer coefficient can be calculated using the following formula:

[0084] k=steer_ratio_dynamic / steer_ratio

[0085] Among them, k is the understeer coefficient, steer_ratio is the fixed steering ratio of the electric steering wheel, and steer_ratio_dynamic is the dynamic steering ratio of the electric steering wheel.

[0086] Furthermore, when calculating the understeering coefficient, the understeering coefficient can be calculated through the navigation receiver and the electric steering wheel data. When calculating, first record the vehicle's running steering angle set {δ1, δ2, δ3...δn} from the current moment and the previous period of time. In addition, we can use the feedback data of the electric steering wheel to record the electric steering wheel angle data set {A1, A2, A3...Am} for a period of time. Since the feedback frequency of the electric steering wheel angle data is higher than the feedback frequency of the angular velocity data, m is greater than n. According to the linear steering model: Δδ can be obtained by the following calculation formula:

[0087] Δδ=ΔA / steer_ratio (1)

[0088] If we consider the dead zone of the vehicle steering system, and assume that the dead zone is a fixed size dead zone, and the dead zone will be reset when the steering wheel is turned in the opposite direction, then when the steering wheel is turned in the same direction for a single time, if the steering amplitude is greater than the dead zone size, we have:

[0089] Δδ=(ΔA_deadzone) / steer_ratio

[0090] If the steering amplitude is smaller than the dead zone size during a single steering in the same direction, then: Δδ=0, and the rotation amount of the electric steering wheel outside the dead zone is the effective rotation amount.

[0091] For the electric steering wheel angle data set {A1, A2, A3...Am}, since the time interval between each data is very short, it can be approximately considered that the steering wheel rotation direction has not changed between two consecutive data, and continuous same-direction rotation can be considered as a single same-direction rotation (dead zone is not reset). Based on this principle, we can calculate the cumulative effective steering wheel rotation amount ΔAfull between A1-Am.

[0092] In addition, for the vehicle running steering angle set {δ1, δ2, δ3...δn}, we can get the cumulative vehicle running steering angle change by the following formula:

[0093] Δδfull=fabs(δ1_δ2)+fabs(δ2_δ3)+...+fabs(δn_1_δn)

[0094] steer_ratio_dynamic=ΔAfull / Δδfull (2)

[0095] Finally, the dynamic steering ratio of the vehicle is calculated according to the above formula (2), that is, the ratio of the electric steering wheel angle change to the vehicle running steering angle change. According to the previous formula k = δ1 / δ0, it can be deduced that:

[0096] k=Δδ1 / Δδ0 (3)

[0097] Where Δδ1 is the change in the actual front wheel steering angle of the vehicle, and Δδ0 is the change in the vehicle running steering angle. According to equations (1), (2), and (3), we can finally get:

[0098] k=steer_ratio_dynamic / steer_ratio

[0099] At this point, the understeering coefficient of the vehicle in the previous period of time has been calculated, so that the vehicle is controlled to take the understeering coefficient into consideration for steering adjustment control during the subsequent driving process.

[0100] In some implementations, the step of acquiring the target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle comprises:

[0101] Get the difference between the actual current steering angle and the actual target steering angle;

[0102] Get the fixed steering ratio of the electric steering wheel;

[0103] The target steering angle of the electric steering wheel is calculated based on the difference and the fixed steering ratio.

[0104] Because on slippery or other unstable steering roads, there is a certain difference between the actual current steering angle and the actual target steering angle, when calculating the target steering angle of the electric steering wheel, the difference and the fixed steering ratio of the electric steering wheel are first obtained. The target steering angle of the electric steering wheel can be obtained by multiplying the difference and the fixed steering ratio, thereby making the steering more precise and able to steer according to the preset trajectory, so that the vehicle's driving trajectory will not deviate from the preset trajectory, thereby solving the technical problem of unstable steering.

[0105] The second aspect of the present application provides an automatic driving control system for agricultural machinery, which adopts the automatic driving control method as described above. Figure 2 As shown, the automatic driving control system includes:

[0106] A navigation receiver is used to obtain the current position information of the agricultural machinery in real time and calculate the relative position deviation of the navigation line;

[0107] Electric steering wheel, used to send steering angle signals of agricultural machinery in real time;

[0108] A calculation module, electrically connected to the electric steering wheel and the navigation receiver, and used for calculating the understeering coefficient of the electric steering wheel according to information fed back by the navigation receiver and the electric steering wheel;

[0109] The control module is electrically connected to the calculation module, and the control module adjusts the steering dynamics of the agricultural machinery in real time according to the understeering coefficient.

[0110] Among them, the navigation receiver is a device that uses GNSS positioning and IMU fusion to obtain the current position and attitude data. The electric steering wheel is a motor steering device used to control the movement direction of agricultural machinery in the agricultural machinery automatic driving control system. It has functions such as its own rotation position feedback to realize the automatic driving of agricultural machinery.

[0111] In the automatic driving control system, the current position information of the vehicle, such as the coordinates in the plane, is first obtained according to the data of the navigation receiver, and then the deviation position information between the current position of the vehicle and the navigation line is determined, and the theoretical target steering angle of the vehicle is determined through the pure tracking control algorithm. The calculation module calculates the understeering coefficient of the electric steering wheel according to the data fed back by the electric steering wheel and the navigation receiver and sends the understeering coefficient information to the control module. The control module sends an adjustment instruction to the agricultural machinery according to the understeering coefficient, so that the agricultural machinery can perform dynamic steering adjustment according to the adjustment instruction, so that the agricultural machinery can automatically drive according to the target path as much as possible.

[0112] In some embodiments, the automatic driving control system further includes a display module electrically connected to the control module, and the display module is used to display current steering dynamic information of the agricultural machinery so that the operator can control the current driving condition in real time.

[0113] In the field of agricultural machinery automatic driving in the prior art, the mainstream hardware solutions on the market include three main components: navigation receiver, electric steering wheel and display tablet. Some solutions also include steering wheel angle sensor. The mainstream solution obtains the real-time motion status of agricultural machinery through navigation receiver and other equipment, and controls the steering wheel of agricultural machinery through electric steering wheel, etc., so as to achieve the purpose of controlling the lateral movement of agricultural machinery and tracking the operation trajectory. In this process, the theoretical target steering angle of the steering wheel that makes the vehicle approach the target trajectory is often calculated first according to the current motion state of the vehicle and the position relationship relative to the target tracking trajectory; then, according to the steering ratio parameters of the vehicle steering system, the corresponding steering wheel rotation target angle is calculated, so that the position of the vehicle steering wheel approaches the theoretical target steering angle. Generally, in the abstract bicycle model, if the theoretical target steering angle of the vehicle is δ, the steering ratio is steer_ratio, and the steering wheel return position angle is 0, then the electric steering wheel rotation target angle calculation formula is:

[0114] θ=δ·steer_ratio

[0115] By comparing the above-mentioned prior art solutions, it can be seen that the prior art does not consider the impact of slipping or understeering on the steering angle, thereby causing the steering to deviate from the preset track. The present invention provides a method for dynamically calculating the vehicle understeering coefficient based on the feedback data of the navigation receiver and the electric steering wheel without a steering wheel angle sensor, and dynamically adjusting the vehicle's steering in real time based on the coefficient, so as to adapt to the automatic driving control scenario where the vehicle slips and understeering conditions change rapidly, and achieve the purpose of improving the trajectory tracking accuracy.

[0116] The third aspect of the present application provides an agricultural machine, including the automatic driving control system as described above. The agricultural machine may be a common agricultural operation vehicle such as a tractor, a corn harvester, a harvester, etc. Since the agricultural machine adopts all the embodiments of the automatic driving control system described above, it has all the beneficial effects brought by the automatic driving control system described above, which will not be described in detail here.

[0117] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0118] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0119] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0120] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for controlling automatic driving of agricultural machinery, characterized in that: The agricultural machine includes an electric steering wheel for controlling steering, and the automatic driving control method includes the steps of: Obtaining a theoretical target steering angle and a theoretical current steering angle of the agricultural machinery; calculating an understeering coefficient of the agricultural machinery during a current driving process; Calculating a current actual target steering angle of the agricultural machinery according to the theoretical target steering angle and the understeering coefficient; Calculating an actual current steering angle of the agricultural machinery according to the theoretical current steering angle and the understeering coefficient; Acquire a target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle; The agricultural machinery is controlled to move according to the target steering angle of the electric steering wheel.

2. The automatic driving control method for agricultural machinery according to claim 1, characterized in that: The step of obtaining the theoretical target steering angle of the agricultural machinery comprises: Obtaining current location information of the agricultural machinery; Calculating the deviation between the current position information of the agricultural machinery and the relative position information of the navigation line; The theoretical target steering angle of the agricultural machinery is obtained according to the deviation between the current position information and the relative position information.

3. The automatic driving control method for agricultural machinery according to claim 1, characterized in that: The theoretical current steering angle is obtained by the following calculation formula: δ=arctan(L·w / v) Wherein, δ is the theoretical current steering angle, v is the driving linear speed of the agricultural machinery, L is the wheelbase of the agricultural machinery, and w is the yaw angular velocity of the agricultural machinery during driving.

4. The automatic driving control method for agricultural machinery according to claim 1, characterized in that: The step of calculating the understeering coefficient of the agricultural machinery during the current driving process comprises: Obtaining a dynamic steering ratio and a fixed steering ratio of the electric steering wheel; An understeering coefficient of the agricultural machinery within a preset time range is calculated according to the dynamic steering ratio of the electric steering wheel and the fixed steering ratio.

5. The automatic driving control method for agricultural machinery according to claim 4, characterized in that: The calculation step of the dynamic steering ratio comprises: Acquire a set of operating steering angles and a set of electric steering wheel angle data of the agricultural machinery within a preset time range; Calculating a change value of an operating steering angle of the agricultural machinery according to the operating steering angle set; Calculating the effective rotation amount of the electric steering wheel according to the electric steering wheel angle data set; The dynamic steering ratio of the electric steering wheel is obtained according to the ratio of the effective rotation amount of the electric steering wheel to the operational steering angle change value.

6. The automatic driving control method for agricultural machinery according to claim 4, characterized in that: The understeer coefficient is obtained by the following calculation formula: k=steer_ratio_dynamic / steer_ratio Wherein, k is the understeering coefficient, steer_ratio is the fixed steering ratio of the electric steering wheel, and steer_ratio_dynamic is the dynamic steering ratio of the electric steering wheel.

7. The automatic driving control method for agricultural machinery according to claim 1, characterized in that: The step of obtaining the target steering angle of the electric steering wheel according to the actual current steering angle and the actual target steering angle comprises: Obtaining a difference between the actual current steering angle and the actual target steering angle; Obtaining a fixed steering ratio of the electric steering wheel; A target steering angle of the electric steering wheel is calculated based on the difference and the fixed steering ratio.

8. An automatic driving control system for agricultural machinery, characterized in that: The automatic driving control method according to any one of claims 1 to 7 is adopted, wherein the automatic driving control system comprises: A navigation receiver, used to obtain the current position information of the agricultural machinery in real time and calculate the relative position deviation of the navigation line; An electric steering wheel, used for transmitting the steering angle of the agricultural machinery in real time; a calculation module, electrically connected to the electric steering wheel and the navigation receiver, the calculation module being used to calculate an understeering coefficient of the electric steering wheel according to information fed back by the navigation receiver and the electric steering wheel; A control module is electrically connected to the calculation module, and the control module adjusts the steering dynamics of the agricultural machinery in real time according to the understeering coefficient.

9. The automatic driving control system for agricultural machinery according to claim 8, characterized in that: The automatic driving control system also includes a display module electrically connected to the control module, and the display module is used to display the current steering dynamic information of the agricultural machinery.

10. An agricultural machine, characterized in that: Comprising an automatic driving control system according to claim 8 or 9.

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