Control system and control method for agricultural tractor with steering mechanism

Abstract

The present invention discloses a control system and a control method for an agricultural tractor with a steering mechanism, and belongs to the technical field of agricultural machinery control. The control system includes a first acquisition unit, a second acquisition unit, a third acquisition unit, a data storage device, a first processing unit, a first controller, a second processing unit, a second controller, and a third processing unit. The present invention combines the steering mechanism, the first arm, and the second arm to determine the operating state data and state change data of the agricultural tractor, and forms a working condition matrix according to the ground slope angle, the walking direction angle, and the state change data, and then predicts the working condition similarity according to the Mahalanobis distance of the two groups of working condition matrices, and then generates a first adjustment instruction or a second adjustment instruction. The present invention can quickly generate adjustment instructions, so that agricultural machinery can quickly adapt to similar working environments. The present invention takes into account the influence of the angle change of the steering mechanism on the stability of the agricultural tractor, and avoids the change of the angle and span causing the body stability to deteriorate.

Description

Technical Field

[0001] The present invention relates to the technical field of agricultural machinery control, and in particular to a control system and a control method of an agricultural tractor with a steering mechanism. Background Art

[0002] Agricultural tractors are usually equipped with multi-degree-of-freedom arms, which are connected to pesticide spray heads, pickers, pruning tools, etc. to achieve the cultivation of crops in patches. As described in International Patent Application Publication No. WO2020108015A1 and Chinese Patent Application Publication No. CN117918124A, these agricultural tractors can adjust the posture of the arms so that the pickers and the like reach the working position, while ensuring the stability of the vehicle body through control schemes. Agricultural tractors have many output components, and using iterative approximation methods to find the optimal operation control scheme will seriously reduce the operation efficiency. Chinese Patent Application Publication No. CN114323022A discloses an auxiliary determination method, device and operating machinery for arm posture. The method first obtains a historical arm posture data set, divides the historical arm posture data set into multiple arm posture data subsets, analyzes the acquired historical arm posture data set, and determines the target arm posture information corresponding to different arm end position data. The method combines historical data to quickly find the current optimal solution and realize rapid operation control of agricultural machinery. In order to improve the working coverage, the boom needs to be connected to the vertical steering mechanism to adjust the working surface while maintaining the forward direction of the tractor. The turning angle of the steering mechanism affects the stability of the vehicle body, so it is necessary to adjust the working parameters of the agricultural tractor in combination with the working state of the steering mechanism and the boom to meet the needs of equipment improvement. Summary of the invention

[0003] In order to solve the defects of the above-mentioned prior art, the present invention proposes a control system and control method for an agricultural tractor with a steering mechanism. The present invention combines the steering mechanism, the first arm and the second arm to determine the state change data of the agricultural tractor, obtains the current working condition according to the ground slope angle, the walking direction angle and the state change data, and then searches for the historical working condition similar to the current working condition, and can quickly generate the first adjustment instruction or the second adjustment instruction, so that the agricultural machinery can quickly adapt to the current working condition similar to the historical working condition.

[0004] The technical solution of the present invention is achieved in this way:

[0005] A control system for an agricultural tractor with a steering mechanism, the agricultural tractor having a frame mechanism, a traveling mechanism, and an operating mechanism, the operating mechanism being mounted on the frame mechanism via a steering mechanism, the operating mechanism comprising a first arm and a second arm, the control system comprising:

[0006] A first collection unit is used to collect operating status data of the steering mechanism, the first arm and the second arm;

[0007] The second collecting unit is used to collect the walking direction angle of the walking mechanism;

[0008] The third acquisition unit is used to collect ground slope data and predict ground slope angle;

[0009] A data storage device for storing historical operating conditions and historical suspension data;

[0010] A first processing unit, used to generate a first adjustment instruction or a second adjustment instruction;

[0011] A first controller, used for controlling the frame mechanism according to the first adjustment instruction or the second adjustment instruction;

[0012] A second processing unit, for generating operation target data of the steering mechanism, the first arm and the second arm;

[0013] The third processing unit is used to update the state change data according to the operation state data and the operation target data.

[0014] Among them, the first processing unit calculates the similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, walking direction angle and state change data. If the maximum working condition similarity is less than the threshold, the first adjustment instruction is generated according to the ground slope angle, walking direction angle and state change data. Otherwise, the historical working condition with the maximum working condition similarity is extracted, the historical suspension data of the historical working condition is retrieved, and the second adjustment instruction is generated according to the historical suspension data.

[0015] In the present invention, the first acquisition device includes multiple groups of inclination sensor units, and the current rotation angle of the steering mechanism, the current rotation angle of the first arm, and the current rotation angle of the second arm are determined based on the inclination sensor units. The third acquisition device includes multiple groups of distance sensor units, and the ground slope data is determined based on the distance sensor units.

[0016] A control method for a control system of the agricultural tractor with a steering mechanism comprises the following steps:

[0017] Step 1: The agricultural tractor enters a driving state, collects operating state data of the steering mechanism, the first arm, and the second arm, and generates state change data according to the operating state data;

[0018] Step 2: Collect the walking direction angle of the walking mechanism and the ground slope data, and predict the ground slope angle according to the ground slope data;

[0019] Step 3: Calculate the similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, walking direction angle and state change data. If the maximum working condition similarity is less than the threshold, proceed to step 4; otherwise, proceed to step 5.

[0020] Step 4: Generate a first adjustment instruction according to the ground slope angle, the walking direction angle, and the state change data, control the frame mechanism according to the first adjustment instruction, and proceed to step 6;

[0021] Step 5: extracting the historical working condition with the maximum working condition similarity, retrieving the historical suspension data of the historical working condition, generating a second adjustment instruction according to the historical suspension data, and controlling the frame mechanism according to the second adjustment instruction;

[0022] Step 6: If the agricultural tractor enters the working state, go to step 7; if the agricultural tractor enters the idling state, end the task; otherwise, return to step 2;

[0023] Step 7: Re-collect the operation status data, generate the operation target data of the steering mechanism, the first arm and the second arm according to the operation position, update the state change data according to the operation status data and the operation target data, and return to step 2.

[0024] In the present invention, in step 1, the operating status data includes the current rotation angle of the steering mechanism, the current rotation angle of the first arm and the current rotation angle of the second arm, the state change data includes the frame offset variable and the frame offset derivative, the current frame offset is calculated according to the current rotation angle of the steering mechanism, the current rotation angle of the first arm and the current rotation angle of the second arm, and the initial value of the frame offset derivative is zero.

[0025] In the present invention, in step 2, the trajectory planning data including the trajectory position of the walking mechanism is extracted, and the ground slope angle of the trajectory position in the ground slope data is extracted.

[0026] In the present invention, in step 3, the operating condition matrices of the historical operating conditions and the current operating conditions are respectively constructed, and the operating condition similarity is predicted according to the covariance distance of the two groups of operating condition matrices.

[0027] In the present invention, in step 4, the current suspension data of the frame mechanism is collected, the target suspension data is calculated according to the ground slope angle, the walking direction angle, and the state change data, and the first adjustment instruction is generated according to the current suspension data and the target suspension data.

[0028] In the present invention, in step 5, the current suspension data of the frame mechanism is collected, and the second adjustment instruction is determined according to the historical suspension data, the current suspension data and the similarity of the working conditions.

[0029] In the present invention, in step 7, the operation target data includes the target angle of the steering mechanism, the target angle of the first arm and the target angle of the second arm. The target angle of the steering mechanism is calculated according to the operation position and the original working surface of the operation mechanism. The target angle of the first arm and the target angle of the second arm are calculated according to the operation position and the dimensional parameters of the operation mechanism.

[0030] In the present invention, in step 7, the frame target offset is calculated according to the target angle of the steering mechanism, the target angle of the first arm, and the target angle of the second arm, and the frame offset variable and the frame offset derivative are updated according to the current frame offset and the frame target offset.

[0031] The control system and control method of the agricultural tractor with a steering mechanism implemented in the present invention have the following beneficial effects: the present invention combines the steering mechanism, the first arm and the second arm to determine the operating state data and state change data of the agricultural tractor, forms a working condition matrix according to the ground slope angle, the walking direction angle, and the state change data, and then predicts the working condition similarity according to the Mahalanobis distance of the two groups of working condition matrices, and searches for historical working conditions similar to the current working conditions. The present invention can quickly generate the first adjustment instruction or the second adjustment instruction, so that the agricultural machinery can quickly adapt to similar working environments. The present invention takes into account the influence of the angle change of the steering mechanism on the stability of the agricultural tractor, and avoids the change of the angle and span causing the body stability to deteriorate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A block diagram of a control system of an agricultural tractor with a steering mechanism according to the present invention;

[0033] Figure 2 is a structural diagram of the agricultural tractor of the present invention;

[0034] Figure 3 A schematic diagram of an agricultural tractor of the present invention;

[0035] Figure 4 It is a flow chart of a control method of a control system of an agricultural tractor with a steering mechanism according to the present invention;

[0036] Figure 5 A schematic diagram of the operating mechanism of the present invention in one direction;

[0037] Figure 6 A schematic diagram of the operating mechanism of the present invention from another direction;

[0038] Figure 7 A schematic diagram of the frame mechanism of the present invention;

[0039] Figure 8 It is a schematic diagram of the horizontal offset of the frame mechanism of the present invention.

[0040] Reference numerals in the drawings: frame mechanism 10 , traveling mechanism 20 , working mechanism 30 , first arm 31 , second arm 32 , agricultural implement 33 , first oil cylinder 34 , second oil cylinder 35 , steering mechanism 40 . DETAILED DESCRIPTION

[0041] In order to more clearly understand the purpose, technical solutions and advantages of the present application, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0042] In order to increase the working range, the working surface of the working mechanism is adjusted by the steering mechanism. The lever effect of the steering mechanism and the working mechanism affects the working efficiency and the stability of the frame mechanism. The control system and control method of the agricultural tractor with a steering mechanism of the present invention can quickly generate a first adjustment instruction or a second adjustment instruction by searching similar historical working conditions according to the current working conditions, so that the agricultural tractor can quickly adapt to the working posture and solve the control problem of the agricultural tractor when the single arm is operated at a long distance. Embodiment 1

[0043] like Figures 1 to 3 This agricultural tractor has a frame mechanism 10, a traveling mechanism 20, and an operating mechanism 30. The frame mechanism 10 includes four sets of hydraulic adjustment components, the traveling mechanism 20 includes an internal combustion engine, a reducer, wheels and other equipment, and the hydraulic adjustment components are installed on the wheels. The operating mechanism 30 is installed on the frame mechanism 10 through a steering mechanism 40, and the operating mechanism 30 includes a first arm 31 and a second arm 32, and the second arm 32 is connected to an agricultural implement 33. Figure 3 In the embodiment, the first oil cylinder 34 and the second oil cylinder 35 adjust the current rotation angle of the first arm 31 and the second arm 32, and each component is connected through a hinge point, and the hinge points are represented by letters A to G. Hinge point A is the connection point between the first oil cylinder 34 and the steering mechanism 40, hinge point B is the connection point between the first arm 31 and the steering mechanism 40, hinge point C is the connection point between the first oil cylinder 34 and the first arm 31, hinge point D is the connection point between the second oil cylinder 35 and the first arm 31, hinge point E is the connection point between the first arm 31 and the second arm 32, hinge point F connects the agricultural implement 33, and hinge point G is the connection point between the second oil cylinder 35 and the second arm 32. The lengths of the first oil cylinder 34 and the second oil cylinder 35 are controlled by the cylinder electro-hydraulic proportional valve.

[0044] The control system of the present invention comprises: a first acquisition unit, a second acquisition unit, a third acquisition unit, a data storage device, a first processing unit, a first controller, a second processing unit, a second controller, a third processing unit and a vehicle-mounted host.

[0045] The first acquisition unit is used to collect the operating status data of the steering mechanism 40, the first arm 31 and the second arm 32. The first acquisition device includes a plurality of tilt sensing units, and the current rotation angle of the steering mechanism 40, the current rotation angle of the first arm 31 and the current rotation angle of the second arm 32 are determined according to the tilt sensing units. The second acquisition unit is used to collect the walking direction angle of the walking mechanism 20. The walking mechanism 20 has a steering controller, and the second acquisition unit collects the angle signal of the steering controller to calculate the walking direction angle. The third acquisition unit is used to collect ground slope data and predict the ground slope angle. The third acquisition unit is, for example, a radar or other equipment. The third acquisition device includes a plurality of distance sensing units, and the ground slope data is determined according to the distance sensing units. The data storage device is used to store historical working conditions and historical suspension data. The data storage device can adopt a Cassandra or HBase storage structure to quickly retrieve historical working conditions and historical suspension data. The first processing unit is used to generate a first adjustment instruction or a second adjustment instruction. The first adjustment instruction and the second adjustment instruction are, for example, a damping adjustment amount or a spring adjustment amount of a hydraulic adjustment component. The vehicle-mounted host is used to complete the whole vehicle control of the agricultural tractor. The vehicle-mounted host can determine the working state of the agricultural tractor and control the first processing unit and the second processing unit. The first controller is used to control the frame mechanism 10 according to the first adjustment instruction or the second adjustment instruction. The second controller is used to control the working mechanism according to the working target data. The second processing unit is used to generate the working target data of the steering mechanism 40, the first arm 31 and the second arm 32. Referring to Example 3, the second processing unit can determine the working target data according to the working position. The third processing unit is used to update the state change data according to the working status data and the working target data. In the working state, the third processing unit periodically updates the state change data so that the first processing unit can receive the latest working status data.

[0046] The first processing unit of the present invention calculates the similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, the travel direction angle and the state change data. If the maximum working condition similarity is less than the threshold, a first adjustment instruction is generated based on the ground slope angle, the travel direction angle and the state change data. Otherwise, the historical working condition with the maximum working condition similarity is extracted, the historical suspension data of the historical working condition is retrieved, and the second adjustment instruction is generated based on the historical suspension data. Compared with the prior art that searches for the optimal state of the current working condition by continuous iterative approximation, the present invention can determine the second adjustment instruction with the help of historical suspension data, can quickly determine the optimal state of the current working condition, improve work efficiency, and enable the agricultural tractor to quickly adapt to similar working environments. Embodiment 2

[0047] like Figures 4 to 8 As shown, a control method of a control system of an agricultural tractor with a steering mechanism of the present invention includes the following steps.

[0048] Step 1: The agricultural tractor enters the driving state, collects the operating state data of the steering mechanism, the first arm and the second arm, and generates state change data according to the operating state data. In this embodiment, the operating state data includes the current rotation angle θ1 of the steering mechanism, the current rotation angle θ2 of the first arm and the current rotation angle θ3 of the second arm. The state change data includes the frame offset variable μ0 and the frame offset derivative Referring to the fourth embodiment, the center of gravity offset of the frame is caused by the current rotation angle of the steering mechanism, the current rotation angle of the first arm, and the current rotation angle of the second arm, and the center of gravity offset of the frame is predicted according to the three-dimensional model of the agricultural tractor, that is, the frame offset variable. In the driving state, the operating mechanism remains stable, the frame offset variable remains unchanged, and the initial value of the frame offset derivative is zero.

[0049] Step 2: Collect the walking direction angle and ground slope data of the walking mechanism, and predict the ground slope angle according to the ground slope data. The present invention can obtain trajectory planning data through a navigation system or a preset working path. At the same time, the ground slope data near the agricultural tractor is obtained according to the third acquisition unit, and the ground slope data includes ground slope angles at multiple different positions. The trajectory planning data includes at least one set of trajectory positions of the walking mechanism, and the ground slope angle of the trajectory position of the next sampling period in the ground slope data is extracted. The first adjustment instruction or the second adjustment instruction of the current sampling period is determined according to the ground slope angle of the next sampling period.

[0050] Step 3: Calculate the working condition similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, walking direction angle and state change data. If the maximum working condition similarity is less than the threshold, proceed to step 4, otherwise, proceed to step 5. The present invention does not limit the specific value of the threshold. To ensure control accuracy, usually 1.8≤threshold<2. The present invention describes the working condition similarity based on the covariance distance of the working condition matrix. The covariance distance is the Mahalanobis distance, which takes into account the correlation between the element values ​​in the matrix. For element values ​​with relatively stable means, the difference between the corresponding element values ​​in the historical working conditions has a greater impact on the working condition similarity.

[0051] Specifically, first construct the working condition matrix X1 of the ground slope angle, walking direction angle, and state change data of the current working condition and the working condition matrix X2 of the ground slope angle, walking direction angle, and state change data of the historical working condition. The Mahalanobis distance S between X1 and X2 is . X3 is the covariance matrix of the operating condition matrix X2 in multiple groups of historical operating conditions. The higher the similarity between X1 and X2, the smaller the Mahalanobis distance. When X1 and X2 are equal, S=0. Operating condition similarity=1 / (1+S), where the denominator plus 1 avoids the situation that S=0 has no solution. The present invention does not limit the specific value of the threshold. In the normal distribution, the Mahalanobis distance is usually less than 2, and the operating condition similarity is usually greater than 0.3. The ground slope angle, walking direction angle, and state change data of the present invention are correlated. To ensure control accuracy, 0.8≤threshold≤1 in the present invention. The state change data of this embodiment includes the frame offset variable and the frame deflection derivative , so the operating condition matrix , β is the ground slope angle, α is the walking direction angle.

[0052] Step 4: Generate a first adjustment instruction according to the ground slope angle, the travel direction angle, and the state change data, control the frame mechanism according to the first adjustment instruction, and enter step 6. When the maximum working condition similarity is less than the threshold, there is no comparable historical working condition, collect the current suspension data of the frame mechanism, and generate and calculate the target suspension data according to the ground slope angle, the travel direction angle, and the state change data. The present invention does not limit the specific method of generating the target suspension data. In a preferred embodiment, the damping coefficient or spring stiffness can be determined by methods such as adaptive control and model predictive control (MPC), which will not be described in detail in the present invention. The leveling speed of methods such as adaptive control and model predictive control (MPC) is slow, but it can ensure that the overall agricultural tractor gradually tends to be stable. The target suspension data includes but is not limited to the damping coefficient and spring stiffness, etc. The total adjustment amount is determined according to the difference between the target suspension data and the current suspension data, and then the first adjustment instruction is generated. Referring to Example 5, the first adjustment instruction includes the damping adjustment amount or spring adjustment amount of the four groups of hydraulic adjustment mechanisms in the current cycle, and multiple single-cycle adjustment amounts are close to the total adjustment amount, so as to gradually achieve the purpose of leveling.

[0053] Step 5: Extract the historical working condition with the maximum working condition similarity, retrieve the historical suspension data of the historical working condition, generate the second adjustment instruction according to the historical suspension data, and control the frame mechanism according to the second adjustment instruction. The historical suspension data refers to the target suspension data obtained under the historical working condition, and the second adjustment instruction is quickly generated with the historical suspension data as a reference. For example, the current suspension data of the frame mechanism is collected, and the total adjustment amount of the spring is determined according to the difference between the historical suspension data and the current suspension data, and then the total adjustment time T is decomposed into the spring adjustment amount k1 within multiple sampling cycles, and then the spring adjustment amount k1 is calibrated twice according to the working condition similarity. The calibrated spring adjustment amount k2=k1×k0 / k0', k0 is the adjustment margin of the current frame mechanism, and k0' is the adjustment margin of the historical frame mechanism.

[0054] Step 6: If the agricultural tractor enters the working state, go to step 7. If the agricultural tractor enters the idling state, end the task, otherwise return to step 2. The on-board host determines the working state of the agricultural tractor, including the driving state, the working state, and the idling state. When the agricultural tractor enters the working state, the working position is monitored and the state change data is updated. When the agricultural tractor enters the driving state, the walking direction angle of the walking mechanism and the ground slope data are continued to be collected.

[0055] Step 7: Recollect the operation status data, generate the operation target data of the steering mechanism, the first arm and the second arm according to the operation position, update the state change data according to the operation status data and the operation target data, and return to step 2. The operation target data includes the target angle of the steering mechanism, the target angle of the first arm and the target angle of the second arm. The target angle of the steering mechanism is calculated according to the operation position and the original working surface of the operation mechanism, and the target angle of the first arm and the target angle of the second arm are calculated according to the operation position and the size parameters of the operation mechanism, as described in Example 3. Then, the mass offset function of the steering mechanism is calculated according to the current angle and target angle of the steering mechanism, the mass offset function of the first arm is calculated according to the current angle and target angle of the first arm, and the mass offset function of the second arm is calculated according to the current angle and target angle of the second arm. The frame offset variable and the frame offset derivative are updated by the mass offset function of the steering mechanism, the mass offset function of the first arm and the mass offset function of the second arm. The calculation process of the frame offset derivative is as described in Example 4. Embodiment 3

[0056] The second arm of this embodiment is connected to the pruning device. The steering mechanism and the operating mechanism are adjusted from the current state to the target state according to the operating state data and the operating target data, so that the pruning device reaches the operating position. Further disclosed is a preferred method for calculating the target rotation angle of the steering mechanism, the target rotation angle of the first arm, and the target rotation angle of the second arm.

[0057] like Figure 5 As shown, the center line of the steering mechanism and the working position form a vertical working plane, and the target rotation angle of the steering mechanism makes the first arm and the second arm of the working mechanism and the working position located on the vertical working plane. The plane where the first arm and the second arm are located is the original working plane. The angle of rotating the original working plane to the vertical working plane is the target rotation angle θ1' of the steering mechanism.

[0058] exist Figure 6 In the figure, the target rotation angle θ2' of the first arm is ∠ABC, and the target rotation angle θ3' of the second arm is ∠DEG. The size parameters include the horizontal distance L1 between the hinge point A and the working position, the height distance h1 between the hinge point A and the working position, the horizontal distance L2 between the hinge point B and the working position, and the height distance h2 between the hinge point B and the working position. The distance L between the hinge point A and the hinge point F is obtained based on the size parameters. AFand the distance L between hinge point B and hinge point F BF . , . Get the distance L between hinge point B and hinge point A BA , according to L BF , L AF and L BA Conclusion , get the distance L between hinge point B and hinge point E BE and the distance L between the hinge point E and the hinge point F EF , according to L BE , L EF and L BF Conclusion Then according to the distance L between hinge point B and hinge point C BC , the distance L between the hinge point C and the hinge point E CE and the distance L between hinge point B and hinge point E BE Get ∠EBC. According to the distance L between the hinge point G and the hinge point E GE , L EF and the distance L between the hinge point G and the hinge point F GF Obtain ∠GEF, according to L BE , L EF and L BF Obtain ∠FEB. According to L BE , the distance L between the hinge point E and the hinge point D ED and the distance L between hinge point B and hinge point D BD Get ∠BED. θ2'=∠ABC=∠ABF+∠FBE+∠EBC, θ3'=∠DEG=360°-∠GEF-∠FEB-∠BED. Embodiment 4

[0059] In agricultural machinery, the movement of the steering mechanism, the first arm, and the second arm causes the center of gravity to shift, which in turn causes the entire vehicle body to shift. The mass shift function of the present invention refers to the shift function of the center of gravity with the motion parameters. The mass shift function g1 of the first arm is a function of the current rotation angle θ1 of the steering mechanism and the current rotation angle θ2 of the first arm, that is, the current offset λ1=g1(θ1, θ2) of the first arm, and the mass shift function g2 of the second arm is a function of the current rotation angle θ1 of the steering mechanism, the current rotation angle θ2 of the first arm, and the current rotation angle θ3 of the second arm, that is, the current offset λ2=g2(θ1, θ2, θ3) of the second arm. The mass shift function refers to the shift function of the center of gravity with the motion parameters. For a specific agricultural tractor, the mass shift function of each component can be obtained through engineering testing or three-dimensional mechanical analysis software (such as ANSYS, MATLAB, etc.). The current offset of the frame μ1=(m0+λ1m1+λ2m2) / (m0+m1+m2), where m0 is the mass of the fixed part of the agricultural tractor (the mass of the agricultural tractor excluding the first arm, the second arm and the agricultural implements), m1 is the mass of the first arm, and m2 is the mass of the second arm (including the terminal agricultural implements).

[0060] Similarly, for the target angle θ1' of the steering mechanism, the target angle θ2' of the first arm, and the target angle θ3' of the second arm, the target offset λ1' of the first arm is g1(θ1', θ2'), and the target offset λ2' of the second arm is g2(θ1', θ2', θ3'). The frame target offset μ2=(m0+λ1'm1+λ2'm2) / (m0+m1+m2). The frame offset variable μ0=μ2-μ1 is calculated based on the current frame offset and the frame target offset. The adjustment speed of the hydraulic adjustment component affects the value of the frame offset derivative. In a simpler embodiment, the hydraulic adjustment component adopts uniform speed adjustment, that is, the frame offset derivative remains unchanged within the adjustment time T, and the frame offset derivative If the hydraulic adjustment component adopts accelerated adjustment, that is, the frame offset derivative increases at a constant speed within the adjustment time T, the frame offset derivative . Embodiment 5

[0061] like Figure 7 and Figure 8 As shown, the frame mechanism 10 includes four groups of hydraulic adjustment components, and the hydraulic adjustment components are connected to the walking mechanism 20. The hydraulic adjustment components include a damping unit and a spring unit, which can provide a predetermined damping coefficient and spring stiffness. When the operating mechanism of the agricultural tractor is working, a first adjustment instruction or a second adjustment instruction is generated according to the working condition matrix to adjust the damping coefficient and the spring stiffness to make the driving process smoother. For agricultural tractors, horizontal stability is more important than vertical vibration reduction performance. The present invention mainly relates to horizontal stability adjustment of agricultural tractors. The mathematical model does not include the force and deformation of the agricultural tractor in the vertical direction.

[0062] This embodiment further discloses determining the damping adjustment amount or the spring adjustment amount in the first adjustment instruction or the second adjustment instruction. For a typical agricultural tractor, the mathematical model of the hydraulic adjustment component is: In the mathematical model, c is the damping coefficient, k is the spring stiffness, and F is the lateral force of the agricultural tractor. In the present invention, the agricultural tractor is on the ground with a ground slope angle of β, and F=sinβ(m0+m1+m2)g. ω1 is the current lateral position of the wheel, ω2 is the target lateral displacement of the wheel, and (ω2-ω1) is the lateral offset of the wheel. Because the agricultural tractor has a slow speed and a small wheel displacement, it can be simplified to ω1=ω2=0. Therefore, the mathematical model of the hydraulic adjustment component is simplified to , g is the acceleration due to gravity.

[0063] By combining the mathematical models at multiple moments, the damping coefficient and spring stiffness at the target state can be obtained. The difference between the damping coefficient and spring stiffness at the target state and the damping coefficient and spring stiffness at the current state is the total damping adjustment amount and the total spring adjustment amount. Then, according to the acceleration adjustment method or the uniform adjustment method, the total adjustment amount is distributed to multiple sampling periods within the adjustment time, and the damping adjustment amount and spring adjustment amount of each sampling period are obtained.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A control system for an agricultural tractor with a steering mechanism, the agricultural tractor having a frame mechanism, a traveling mechanism, and an operating mechanism, the operating mechanism being mounted on the frame mechanism via a steering mechanism, the operating mechanism comprising a first arm and a second arm, characterized in that: The control system includes: A first collection unit is used to collect operating status data of the steering mechanism, the first arm and the second arm; The second collecting unit is used to collect the walking direction angle of the walking mechanism; The third acquisition unit is used to collect ground slope data and predict ground slope angle; A data storage device for storing historical operating conditions and historical suspension data; A first processing unit, used to generate a first adjustment instruction or a second adjustment instruction; A first controller, used for controlling the frame mechanism according to the first adjustment instruction or the second adjustment instruction; A second processing unit, for generating operation target data of the steering mechanism, the first arm and the second arm; The third processing unit is used to update the state change data according to the operation state data and the operation target data. Among them, the first processing unit calculates the similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, walking direction angle and state change data. If the maximum working condition similarity is less than the threshold, the first adjustment instruction is generated according to the ground slope angle, walking direction angle and state change data. Otherwise, the historical working condition with the maximum working condition similarity is extracted, the historical suspension data of the historical working condition is retrieved, and the second adjustment instruction is generated according to the historical suspension data.

2. The control system of the agricultural tractor with a steering mechanism according to claim 1, characterized in that: The first acquisition device includes multiple groups of inclination sensor units, which determine the current rotation angle of the steering mechanism, the current rotation angle of the first arm and the current rotation angle of the second arm according to the inclination sensor units. The third acquisition device includes multiple groups of distance sensor units, which determine the ground slope data according to the distance sensor units.

3. A control method for a control system of an agricultural tractor with a steering mechanism according to claim 1, characterized in that: The following steps are involved: Step 1: The agricultural tractor enters a driving state, collects operating state data of the steering mechanism, the first arm, and the second arm, and generates state change data according to the operating state data; Step 2: Collect the walking direction angle of the walking mechanism and the ground slope data, and predict the ground slope angle according to the ground slope data; Step 3: Calculate the similarity between the current working condition and multiple groups of historical working conditions based on the ground slope angle, walking direction angle and state change data. If the maximum working condition similarity is less than the threshold, proceed to step 4; otherwise, proceed to step 5. Step 4: Generate a first adjustment instruction according to the ground slope angle, the walking direction angle, and the state change data, control the frame mechanism according to the first adjustment instruction, and proceed to step 6; Step 5: extracting the historical working condition with the maximum working condition similarity, retrieving the historical suspension data of the historical working condition, generating a second adjustment instruction according to the historical suspension data, and controlling the frame mechanism according to the second adjustment instruction; Step 6: If the agricultural tractor enters the working state, go to step 7; if the agricultural tractor enters the idling state, end the task; otherwise, return to step 2; Step 7: Re-collect the operation status data, generate the operation target data of the steering mechanism, the first arm and the second arm according to the operation position, update the state change data according to the operation status data and the operation target data, and return to step 2.

4. The control method according to claim 3, characterized in that: In step 1, the operating status data includes the current rotation angle of the steering mechanism, the current rotation angle of the first arm and the current rotation angle of the second arm, and the state change data includes the frame offset variable and the frame offset derivative. The current frame offset is calculated based on the current rotation angle of the steering mechanism, the current rotation angle of the first arm and the current rotation angle of the second arm, and the initial value of the frame offset derivative is zero.

5. The control method according to claim 3, characterized in that: In step 2, the trajectory planning data including the trajectory position of the walking mechanism is extracted, and the ground slope angle of the trajectory position in the ground slope data is extracted.

6. The control method according to claim 3, characterized in that: In step 3, the operating condition matrices of the historical operating conditions and the current operating conditions are constructed respectively, and the operating condition similarity is predicted based on the covariance distance of the two sets of operating condition matrices.

7. The control method according to claim 3, characterized in that: In step 4, the current suspension data of the frame mechanism is collected, the target suspension data is calculated according to the ground slope angle, the walking direction angle, and the state change data, and the first adjustment instruction is generated according to the current suspension data and the target suspension data.

8. The control method according to claim 3, characterized in that: In step 5, current suspension data of the frame mechanism is collected, and a second adjustment instruction is determined according to historical suspension data, current suspension data, and working condition similarity.

9. The control method according to claim 4, characterized in that: In step 7, the operation target data includes the target angle of the steering mechanism, the target angle of the first arm and the target angle of the second arm. The target angle of the steering mechanism is calculated according to the operation position and the original working surface of the operation mechanism. The target angle of the first arm and the target angle of the second arm are calculated according to the operation position and the dimensional parameters of the operation mechanism.

10. The control method according to claim 9, characterized in that: In step 7, the target offset of the frame is calculated according to the target angle of the steering mechanism, the target angle of the first arm, and the target angle of the second arm, and the frame offset variable and the frame offset derivative are updated according to the current offset of the frame and the target offset of the frame.

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