Agricultural work vehicle and method for correcting direction error and steering angle error thereof

Abstract

A method for correcting a direction error and a steering angle error of an agricultural working vehicle may comprise the steps of: acquiring, by using a heading sensor, a first measurement value corresponding to a forward direction of the vehicle, and acquiring, by using a steering angle sensor, a second measurement value corresponding to a state in which the front wheels of the vehicle are centrally aligned by a user's operation; generating a reference path on the basis of the first measurement value; acquiring an actual movement direction of the vehicle while the vehicle travels while following the reference path, and correcting a direction error on the basis of the first measurement value and the actual movement direction; acquiring an actual movement path of the vehicle while the vehicle travels while following the reference path; and determining a steering neutral value on the basis of the second measurement value and the actual movement path.

Description

Agricultural work vehicles and methods for correcting their direction error and steering angle error

[0001] The present disclosure relates to an agricultural work vehicle and a method for correcting the direction error and steering angle error thereof.

[0002] Agricultural work vehicles are vehicles used for agricultural work, and may refer to, for example, rice transplanters, combines, tractors, etc. For example, a tractor can be attached to various implements required for agricultural work and perform the necessary agricultural work.

[0003] With the application of Tier 4 engines, automatic transmissions, and automatic hydraulic systems to agricultural work vehicles, and the introduction of information technology (IT), autonomous operation technology is being developed that enables agricultural work vehicles to perform agricultural tasks without human intervention. For example, in Level 3 autonomous operation, a worker must be on board the agricultural work vehicle to monitor and control the autonomous operation, whereas in Level 5 autonomous operation, the agricultural work vehicle directly determines work-related elements and performs the task regardless of whether a worker is on board.

[0004] For successful and efficient autonomous operation, agricultural work vehicles must be able to precisely follow a set work path within the work site. To this end, agricultural work vehicles are equipped with various types of sensors, including position, heading, and steering angle sensors, and the vehicles follow the work path based on the measurements from these sensors.

[0005] For precise tracking of the work path, it is necessary to ensure that sensor measurements are identical to or as similar as possible to the actual values. This is because if there is an error in the sensor measurements, the work is actually performed on a different path or in a different area, even if the agricultural work vehicle perceives that it is correctly tracking the work path. Since errors (e.g., offset) in measurements occur due to various factors such as the sensor assembly method, installation location, temperature, and humidity, a method to correct the error between the sensor measurements and the actual values ​​is required.

[0006] The present disclosure is intended to provide a method for correcting the error between the measured value and the actual value of a sensor mounted on an agricultural work vehicle without relying on human senses.

[0007] According to one aspect of the present disclosure, a method for correcting a direction error and a steering angle error of an agricultural work vehicle may include the steps of: obtaining a first measurement value corresponding to the forward direction of the agricultural work vehicle using a direction sensor; obtaining a second measurement value corresponding to a state in which the front wheels of the agricultural work vehicle are centrally aligned by user operation using a steering angle sensor; generating a reference path based on the first measurement value; obtaining an actual direction of movement of the agricultural work vehicle while the agricultural work vehicle is driving while following the reference path; correcting a direction error based on the first measurement value and the actual direction of movement; and obtaining an actual path of movement of the agricultural work vehicle while the agricultural work vehicle is driving while following the reference path, and determining a steering neutral value based on the second measurement value and the actual path of movement.

[0008] In one embodiment, the step of acquiring the second measurement value may include displaying a message in the HMI guiding a user to operate the steering wheel to a neutral position, and acquiring the measurement value of the steering angle sensor as the second measurement value when the steering wheel is operated to a neutral position by the user.

[0009] In one embodiment, the step of obtaining the second measurement value may include: displaying a message on the HMI guiding the user to operate the steering wheel to a maximum rotation position in a first direction, either clockwise or counterclockwise; obtaining a third measurement value of the steering angle sensor when the steering wheel is operated to a maximum rotation position in the first direction by the user; displaying a message on the HMI guiding the user to operate the steering wheel to a maximum rotation position in a second direction opposite to the first direction; obtaining a fourth measurement value of the steering angle sensor when the steering wheel is operated to a maximum rotation position in the second direction by the user; and obtaining the median value of the third measurement value and the fourth measurement value as the second measurement value.

[0010] In one embodiment, the reference path may be a straight path facing the direction corresponding to the first measurement value from the current position of the agricultural work vehicle.

[0011] In one embodiment, the step of correcting the direction error may include: acquiring a plurality of first position measurements while driving while following the reference path; determining the actual direction of movement based on the plurality of first position measurements; calculating a heading offset, which is the difference between the direction corresponding to the first measurements and the actual direction of movement; and correcting the direction error by applying the heading offset to the measurements of the direction sensor.

[0012] In one embodiment, the step of determining the actual direction of movement based on the plurality of position measurements may be determined by applying at least one algorithm among linear regression, moving average, Kalman filtering, or principal component analysis (PCA) to the plurality of position measurements, or by calculating a vector determined by two of the plurality of position measurements.

[0013] In one embodiment, after the step of correcting the direction error, the step of returning to the original position via reverse may be further included to perform the step of determining the steering neutral value.

[0014] In one embodiment, the step of determining the steering neutral value may include: acquiring a plurality of second position measurements corresponding to the actual travel path while driving while following the reference path at a reference speed; calculating the bias and oscillation of the lateral error between the actual travel path and the reference path based on the plurality of second position measurements; determining whether the magnitude of the bias of the lateral error is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value; if the bias of the lateral error is greater than the first reference value or the oscillation of the lateral error is greater than the second reference value, adjusting the current steering neutral value based on the bias and oscillation of the lateral error; and, based on the adjusted steering neutral value, repeating the steps of acquiring the plurality of second position measurements, calculating the bias and oscillation of the lateral error, and determining whether the magnitude of the bias of the lateral error is less than or equal to the first reference value and the oscillation of the lateral error is less than or equal to the second reference value. In an embodiment, the step of adjusting the current steering neutral value may include the step of determining the adjustment direction of the current steering neutral value based on the deviation of the lateral error, and the step of determining the adjustment magnitude of the current steering neutral value based on the shaking of the lateral error.

[0015] In one embodiment, the reference speed may be a first speed among a plurality of preset speeds, and the step of determining the steering neutral value may further include: determining whether the steering angle error correction is completed for all preset reference speeds if the magnitude of the deviation of the lateral error is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value; changing the reference speed if the steering angle error correction is not completed for all preset reference speeds; and based on the changed reference speed, obtaining the plurality of second position measurements, calculating the deviation and oscillation of the lateral error, determining whether the magnitude of the deviation of the lateral error is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value, and repeating the step of adjusting the current steering neutral value.

[0016] In one embodiment, the step of changing the reference speed may include: changing the reference speed to a second speed different from the first speed among the preset multiple speeds; changing the reference speed back to the first speed if the magnitude of the deviation of the lateral error calculated based on the reference speed changed to the second speed is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value; and changing the reference speed to a third speed different from the first speed and the second speed among the preset multiple speeds if the magnitude of the deviation of the lateral error calculated based on the reference speed changed back to the first speed is less than or equal to the first reference value and the oscillation of the lateral error is less than or equal to a second reference value.

[0017] In one embodiment, the step of determining the steering neutral value may further include the step of terminating the step of determining the steering neutral value when the correction of the steering angle error for all preset reference speeds is completed.

[0018] According to one aspect of the present disclosure, an agricultural work vehicle comprises a direction sensor for measuring the forward direction of the agricultural work vehicle, a steering angle sensor for measuring the steering angle of the agricultural work vehicle, a memory for storing one or more instructions, and at least one processor. When the one or more instructions are executed by the at least one processor, the agricultural work vehicle may obtain a first measurement value corresponding to the forward direction of the agricultural work vehicle using the direction sensor, obtain a second measurement value corresponding to a state in which the front wheels of the agricultural work vehicle are centered by user operation using the steering angle sensor, generate a reference path based on the first measurement value, obtain the actual direction of movement of the agricultural work vehicle while the agricultural work vehicle is driving while following the reference path, correct a direction error based on the first measurement value and the actual direction of movement, obtain the actual path of movement of the agricultural work vehicle while the agricultural work vehicle is driving while following the reference path, and determine a steering neutral value based on the second measurement value and the actual path of movement.

[0019] According to a method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment, the error between the measured value of a sensor mounted on the agricultural work vehicle and the actual value can be corrected without relying on human senses.

[0020] According to a method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment, by causing the agricultural work vehicle to return to its original position through reverse movement to correct the steering angle error after correcting the direction error, direction correction and steering angle correction can be performed even when the cultivated land is narrow or the starting position is close to the boundary surface.

[0021] FIG. 1 is a block diagram illustrating the components of an agricultural work vehicle according to one embodiment.

[0022] FIG. 2 is a flowchart illustrating a method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment.

[0023] FIG. 3 is a reference diagram for explaining the process of obtaining a measurement value of a steering angle sensor through a user according to one embodiment.

[0024] FIG. 4 is a flowchart illustrating a method for correcting a direction error of an agricultural work vehicle according to one embodiment.

[0025] FIG. 5 is a reference diagram for explaining a method to obtain the actual direction of movement of an agricultural work vehicle according to one embodiment.

[0026] FIG. 6 is a flowchart illustrating a method for determining the steering neutral value of an agricultural work vehicle according to one embodiment.

[0027] FIG. 7 is a reference diagram for explaining the deviation and shaking of the lateral error between the actual movement path and the reference path according to one embodiment.

[0028] The terms used in this disclosure have been selected to be as widely used and general as possible, taking into account their functions within this disclosure; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. In specific cases, terms have been selected at the applicant's discretion, and in such cases, their meanings will be described in detail in the relevant explanatory sections. Therefore, terms used in this disclosure should be defined not merely by their names, but based on their meanings and the overall content of this disclosure.

[0029] Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art as described in this specification.

[0030] In this disclosure, the term “and / or” includes a combination of a plurality of related described components or any of a plurality of related described components.

[0031] Terms including ordinal numbers, such as “first” or “second,” used in this disclosure may be used to describe various components, but said components should not be limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another.

[0032] In the present disclosure, the expression “at least one of a, b, or c” may refer to “a,” “b,” “c,” “a and b,” “a and c,” “b and c,” “all of a, b, and c,” or variations thereof.

[0033] When a part of a specification is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Furthermore, terms such as “part” and “module” as used in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware or software, or as a combination of hardware and software.

[0034] Hereinafter, embodiments of the present disclosure are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals. In addition, the reference numerals used in each drawing are for the purpose of explaining each drawing, and different reference numerals used in different drawings are not intended to represent different elements.

[0035] The present disclosure relates to a method for correcting direction errors and steering angle errors of an agricultural work vehicle.

[0036] In the present disclosure, the direction error may refer to the difference between the measurement of a direction sensor mounted on an agricultural work vehicle and the actual forward direction of the agricultural work vehicle. The forward direction measured by the direction sensor may differ from the actual forward direction due to the direction sensor being installed in the wrong direction, an error in the direction sensor itself, or environmental factors (e.g., temperature, humidity).

[0037] A method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment can correct the direction error by calculating the direction error through the operations described below and adding or subtracting the calculated direction error from the measurement value of the direction sensor.

[0038] In the present disclosure, steering angle error may refer to the difference between the current steering neutral value and the actual steering neutral value. The steering neutral value refers to the measurement value of the steering angle sensor that serves as a reference for an agricultural work vehicle to recognize that the front wheels are in a centered state. The current steering neutral value refers to the current set value of the steering neutral value. The actual steering neutral value refers to the measurement value of the steering angle sensor when the front wheels are actually centered, and is the target value that the steering neutral value must reach through steering angle error correction.

[0039] To accurately control the steering angle during autonomous driving, it is necessary to precisely determine the steering neutral value. For example, the measurement from the steering angle sensor when the front wheels are centered by the user's steering wheel operation can be determined as the steering neutral value. However, determining the steering neutral value based on the user's subjective senses hinders autonomous driving performance, as there is a possibility that the value may be set differently depending on the user or inaccurately due to individual user error.

[0040] A method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment can correct the steering angle error by determining an initial value of the steering neutral value after correcting the direction error, and by modifying or updating the current steering neutral value (i.e., the initial value, or the most recently modified or updated value) to become the actual steering neutral value through the operations described below.

[0041] FIG. 1 is a block diagram illustrating the components of an agricultural work vehicle according to one embodiment.

[0042] Referring to FIG. 1, an agricultural work vehicle (100) may include a position sensor (110), a direction sensor (120), a steering angle sensor (130), a human-machine interface (HMI) (140), a memory (150), and a processor (160). However, not all of the illustrated components are essential components. An agricultural work vehicle (100) may be implemented with more components than those illustrated in FIG. 1, or with fewer components.

[0043] A position sensor (110) can measure the position of an agricultural work vehicle (100). The position sensor (110) can transmit the position measurement value to a processor (160). The measurement value of the position sensor (110) can be used to obtain the actual direction of movement and the actual path of movement of the agricultural work vehicle (100). For example, the position sensor (110) may be any one of a GNSS (global navigation satellite system), GPS (global navigation satellite system), RTK-GNSS (real-time kinematic GNSS), or DGPS (differential GPS), but is not limited thereto.

[0044] The direction sensor (120) can measure the forward direction of the agricultural work vehicle (100). The direction sensor (120) can transmit the direction measurement value to the processor (160). For example, the direction sensor (120) may be any one of GNSS, IMU (inertial measurement unit), electronic compass, or fluxgate compass, but is not limited thereto.

[0045] In one embodiment, the position sensor (110) and the direction sensor (120) may be implemented as a single sensor module capable of measuring both the position and the forward direction of the agricultural work vehicle (100). For example, a dual antenna GNSS that measures the position using satellite signals and measures the forward direction using a direction vector between two antennas may be employed as the position sensor (110) and the direction sensor (120).

[0046] The steering angle sensor (130) can measure the steering angle of an agricultural work vehicle (100). The steering angle may refer to the angle of the front wheel relative to the forward direction. The steering angle sensor (130) can transmit the steering angle measurement value to a processor (160). For example, the steering angle sensor (130) can measure the steering angle using a potentiometer method, an optical method, or a magnetic method, but is not limited thereto.

[0047] The HMI (140) can provide an interface that allows the user and the agricultural work vehicle (100) to interact. For example, the HMI (140) may include a display that displays a message instructing the user to operate the steering wheel.

[0048] The memory (150) may store one or more instructions or programs that can be executed by the processor (160). The operations of the agricultural work vehicle (100) described in this disclosure may be implemented by executing one or more instructions or programs stored in the memory (150) by the processor (160).

[0049] The memory (150) may include at least one of flash memory, hard disk, RAM (Random Access Memory), SRAM (Static Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable Read-Only Memory), but is not limited thereto.

[0050] The processor (160) can control the overall operations of the agricultural work vehicle (100). For example, the processor (160) can control the operations performed by the agricultural work vehicle (100) to correct direction errors and steering angle errors by executing one or more instructions or programs stored in memory (150). There may be one or more processors (160).

[0051] The processor (160) may be composed of at least one of, for example, a CPU (Central Processing Unit), an MCU (Micro Controller Unit), a DSP (Digital Signal Processor), a microprocessor, a GPU (Graphics Processing Unit), an NPU (Neural Processing Unit), an AP (Application Processor), an ASIC (Application Specific Integrated Circuit), an ECU (Electronic Control Unit), a TCU (Transmission Control Unit), or a VCU (Vehicle Control Unit), but is not limited thereto.

[0052] FIG. 2 is a flowchart for explaining a method for correcting direction error and steering angle error of an agricultural work vehicle according to one embodiment, and FIG. 3 is a reference diagram for explaining a process of obtaining a measurement value of a steering angle sensor through a user according to one embodiment.

[0053] Referring to FIG. 2, in operation 210, the agricultural work vehicle (100) can obtain a first measurement value corresponding to the forward direction of the agricultural work vehicle (100) using a direction sensor (120), and obtain a second measurement value corresponding to the state in which the front wheels of the agricultural work vehicle (100) are centrally aligned by user operation using a steering angle sensor (130).

[0054] An agricultural work vehicle (100) displays a message through an HMI (140) that guides (or induces) the user to operate the steering wheel, and when the user operates the steering wheel according to the message, the measurement value of the corresponding steering angle sensor (130) can be obtained. At this time, the HMI (140) can display the real-time measurement value of the steering angle sensor (130) according to the operation state of the steering wheel.

[0055] As shown in the example of 310 in FIG. 3, when a message is displayed on the HMI (140) guiding (or inducing) the user to operate the steering wheel to the maximum clockwise rotation position, the user rotates the steering wheel clockwise to the end, and the agricultural work vehicle (100) can obtain a measurement value from the steering angle sensor (130) corresponding to the state where the front wheel is steered to the maximum right.

[0056] As shown in the example of 320 in FIG. 3, when a message is displayed on the HMI (140) guiding (or inducing) the user to operate the steering wheel to the maximum counterclockwise rotation position, the user rotates the steering wheel counterclockwise to the end, and the agricultural work vehicle (100) can obtain a measurement value from the steering angle sensor (130) corresponding to the state where the front wheel is steered to the maximum left.

[0057] As shown in the example of 330 in FIG. 3, when a message is displayed on the HMI (140) guiding (or inducing) the user to operate the steering wheel to a neutral position, the user operates the steering wheel to a neutral position, and the agricultural work vehicle (100) can obtain a measurement value (i.e., a second measurement value) of the steering angle sensor (130) corresponding to the state in which the front wheels are centered by the user's operation.

[0058] In one embodiment, the agricultural work vehicle (100) may obtain a second measurement value of the measurement value of the steering angle sensor (130) corresponding to the state where the front wheel is steered to the right to the maximum and the measurement value of the steering angle sensor (130) corresponding to the state where the front wheel is steered to the left to the maximum.

[0059] The first measurement value obtained in operation 210 may contain measurement errors due to the various causes mentioned above, and the second measurement value may differ from the actual steering neutral value as it is a value measured based on the user's senses.

[0060] The agricultural work vehicle (100) can set the acquired second measurement value as the initial value of the steering neutral value.

[0061] In operation 220, the agricultural work vehicle (100) can generate a reference path based on a first measurement. The reference path is a path that the agricultural work vehicle (100) follows to correct direction errors and steering angle errors in subsequent operations. For example, the reference path may be a straight path from the current position of the agricultural work vehicle (100) toward a direction corresponding to the first measurement, but is not limited thereto. The agricultural work vehicle (100) may follow the reference path using a path following algorithm such as PID (proportional-integral-derivative) control, pure pursuit algorithm, Stanley algorithm, model predictive control (MPC), etc., but is not limited thereto.

[0062] In operation 230, the agricultural work vehicle (100) obtains the actual direction of movement of the agricultural work vehicle (100) while driving along a reference path, and can correct the direction error based on the first measurement value and the actual direction of movement. Operation 230 will be described in detail later with reference to FIGS. 4 and FIGS. 5.

[0063] In operation 240, while the agricultural work vehicle (100) is driving while following a reference path, the actual movement path of the agricultural work vehicle (100) is obtained, and a steering neutral value can be determined based on the second measurement value and the actual movement path. Operation 240 will be described in detail later with reference to FIGS. 6 and FIGS. 7.

[0064] FIG. 4 is a flowchart for explaining a method for correcting a direction error of an agricultural work vehicle according to one embodiment, and FIG. 5 is a reference diagram for explaining a method for obtaining the actual direction of movement of an agricultural work vehicle according to one embodiment.

[0065] Referring to FIGS. 4 and 5, in operation 410, an agricultural work vehicle (100) can acquire a plurality of first position measurements while driving while following a reference path. The agricultural work vehicle (100) can acquire a plurality of first position measurements using a position sensor (110). As an example, the agricultural work vehicle (100) can follow a reference path using a path following algorithm. As another example, the agricultural work vehicle (100) may follow a reference path by driving straight without steering the front wheels.

[0066] In operation 420, the agricultural work vehicle (100) can determine the actual direction of movement based on a plurality of first position measurements. As an example, the agricultural work vehicle (100) can determine the actual direction of movement by applying at least one algorithm of linear regression, moving average, Kalman filtering, or principal component analysis (PCA) to the plurality of first position measurements. As another example, the agricultural work vehicle (100) may determine the actual direction of movement by calculating a vector determined by two of the plurality of first position measurements.

[0067] Operations 410 and 420 will be explained in more detail with reference to FIG. 5.

[0068] Figure 5 illustrates an example where the reference path is a straight path, but as previously mentioned, the type of reference path is not limited to this.

[0069] As shown in FIG. 5, when an agricultural work vehicle (100) is actually facing northwest (NW) but a directional error occurs and the first measurement points north (N), a reference path is generated to face north.

[0070] Since the agricultural work vehicle (100) follows a reference path based on a measurement that includes a directional error, it actually moves in a direction different from the reference path. As a result, while driving while following the reference path, multiple first position measurements (e.g., P1, P2, P3, P4, P5, P6) are obtained along the actual direction of movement.

[0071] In an example where an agricultural work vehicle (100) follows a reference path using a path-following algorithm, the front wheels are repeatedly steered, so multiple first position measurements are not obtained on a single straight line. In this case, the agricultural work vehicle (100) can determine the actual direction of movement using a trend analysis algorithm such as linear regression analysis, moving average, Kalman filtering, or principal component analysis.

[0072] In an example where an agricultural work vehicle (100) follows a reference path by moving straight without steering the front wheels, a plurality of first position measurements are obtained on a single straight line, such as P1 and P6 in FIG. 5. In this case, the agricultural work vehicle (100) can determine the actual direction of movement by calculating a vector determined by two of the plurality of first position measurements (e.g., P1 and P6).

[0073] In operation 430, the agricultural work vehicle (100) can calculate a heading offset, which is the difference between the direction corresponding to the first measurement and the actual direction of movement. For example, the heading offset can be calculated by subtracting the direction (angle) corresponding to the first measurement from the actual direction (angle) of movement.

[0074] In operation 440, the agricultural work vehicle (100) can correct the direction error by applying a direction offset to the measurement value of the direction sensor (120). For example, the agricultural work vehicle (100) can correct the direction error by adding or subtracting the calculated direction offset from the measurement value of the direction sensor (120). As a result, the agricultural work vehicle (100) can accurately identify the direction by recognizing the value to which the direction offset is applied to the measurement value of the direction sensor (120) as the forward direction.

[0075] After the operations of FIG. 4, the agricultural work vehicle (100) can return to its original position by reversing to perform operations to determine the steering neutral value. For example, the agricultural work vehicle (100) can return to its original position by following a reference path in operation 410, saving its movement path, and then moving in the reverse direction. Through this, the agricultural work vehicle (100) can automatically perform direction correction and steering angle correction without user intervention, and can perform direction correction and steering angle correction even when the cultivated land is narrow or the starting position is close to the boundary surface.

[0076] FIG. 6 is a flowchart for explaining a method for determining the steering neutral value of an agricultural work vehicle according to one embodiment, and FIG. 7 is a reference diagram for explaining the deviation and shaking of the lateral error between an actual travel path and a reference path according to one embodiment.

[0077] Referring to FIGS. 6 and 7, in operation 610, an agricultural work vehicle (100) can acquire a plurality of second position measurements while driving while following a reference path at a reference speed. The agricultural work vehicle (100) can acquire a plurality of second position measurements using a position sensor (110). For example, the agricultural work vehicle (100) can follow a reference path using a path following algorithm.

[0078] The multiple second position measurements obtained correspond to the actual movement path. Since operation 610 is performed after the direction error is corrected, even if the agricultural work vehicle (100) follows the same reference path, the second position measurements obtained in operation 610 are different from the first position measurements obtained in operation 410.

[0079] Since the path-following performance and steering angle error of the agricultural work vehicle (100) may vary depending on the speed of movement, multiple reference speeds may be pre-set to correct the steering angle error at various speeds. For example, if two reference speeds are pre-set, the agricultural work vehicle (100) can perform operation 610 at a first speed (e.g., 1 km / h), and if the reference speed is changed to a second speed (e.g., 5 km / h) in operation 660 described later, the agricultural work vehicle (100) can re-perform operation 610 at the second reference speed.

[0080] In operation 620, the agricultural work vehicle (100) can calculate the bias and oscillation of the lateral error between the actual travel path and the reference path based on a plurality of second position measurements. The bias is a representative value of the lateral error and may be, for example, any one of the mean, median, or mode, but is not limited thereto. The oscillation is a scatter of the lateral error and may be, for example, any one of the standard deviation, variance, or maximum-minimum range of the lateral error, but is not limited thereto.

[0081] As illustrated in FIG. 7, when an agricultural work vehicle (100) follows a reference path, the front wheels are repeatedly steered, so the actual travel path may be a zigzag shape that crosses the reference path left and right. If the current steering neutral value is different from the actual steering neutral value, a significant lateral distance error may occur between the actual travel path and the reference path, even if the agricultural work vehicle (100) recognizes that it is correctly following the work path. In this case, the deviation of the lateral error may correspond to the distance between the average travel path of the actual travel path and the reference path, and the oscillation of the lateral error may correspond to the width of the actual travel path (e.g., zigzag shape).

[0082] In operation 630, the agricultural work vehicle (100) can determine whether the magnitude of the deviation of the lateral error is less than or equal to a first reference value and whether the oscillation of the lateral error is less than or equal to a second reference value. For example, the first reference value may be 0.5 cm and the second reference value may be 1 cm, but is not limited thereto.

[0083] In operation 640, the agricultural work vehicle (100) can adjust the current steering neutral value based on the deviation and oscillation of the lateral error if the deviation of the lateral error is greater than the first reference value or the oscillation of the lateral error is greater than the second reference value. The current steering neutral value may be the second measurement value set as the initial value in operation 210, or the value adjusted in the most recently performed operation 640.

[0084] The agricultural work vehicle (100) can adjust the current steering neutral value in a direction such that the deviation and shaking of the lateral error are each less than or equal to the first reference value and the second reference value.

[0085] The agricultural work vehicle (100) can determine the direction of adjustment of the current steering neutral value based on the deviation of the lateral error. For example, as shown in the example of FIG. 7, the agricultural work vehicle (100) can increase the current steering neutral value when the average travel path of the actual travel path is located to the left of the reference path (e.g., when the deviation is less than 0). Conversely, the agricultural work vehicle (100) can decrease the current steering neutral value when the average travel path of the actual travel path is located to the right of the reference path (e.g., when the deviation is greater than 0).

[0086] The agricultural work vehicle (100) can determine the adjustment size of the current steering neutral value based on the lateral error shaking. For example, the agricultural work vehicle (100) can adjust the current steering neutral value more as the lateral error shaking is greater.

[0087] The agricultural work vehicle (100) can repeatedly perform operations 610, 620, 630 and 640 until the magnitude of the deviation of the lateral error becomes less than or equal to a first reference value and the shaking of the lateral error becomes less than or equal to a second reference value.

[0088] In operation 650, the agricultural work vehicle (100) can determine whether correction has been completed for all preset reference speeds if the magnitude of the deviation of the lateral error is less than or equal to the first reference value and the shaking of the lateral error is less than or equal to the second reference value.

[0089] In operation 660, the agricultural work vehicle (100) may change the reference speed if corrections for all preset reference speeds have not been completed, and may repeat operations 610, 620, 630, and 640 for the changed reference speed. For example, if three reference speeds are preset, the agricultural work vehicle (100) may change the reference speed to a second speed (e.g., 5 km / h) if the condition of operation 630 is satisfied as a result of performing operations 610, 620, 630, and 640 based on a first speed (e.g., 1 km / h). The agricultural work vehicle (100) may change the reference speed to a third speed (e.g., 10 km / h) if the condition of operation 630 is satisfied as a result of repeating operations 610, 620, 630, and 640 based on the reference speed changed to the second speed. The agricultural work vehicle (100) can repeat operations 610, 620, 630 and 640 based on the reference speed changed to the third speed.

[0090] In one embodiment, if the condition of operation 630 is satisfied as a result of re-performing operations 610, 620, 630, and 640 based on a changed reference speed, the agricultural work vehicle (100) may change the reference speed back to the previous speed and re-perform operations 610, 620, 630, and 640. If the condition of operation 630 is satisfied as a result of re-performing operations 610, 620, 630, and 640 based on a reference speed that has returned to the previous speed, the agricultural work vehicle (100) may change the reference speed back to the new speed and re-perform operations 610, 620, 630, and 640. This method is intended to find a steering neutral value that satisfies the conditions of operation 630 for all preset reference speeds, and can be understood as a procedure to check whether the steering neutral value that satisfies the conditions of operation 630 at the changed reference speed still satisfies the conditions of operation 630 at the previous reference speed.

[0091] For example, if three reference speeds are preset, the agricultural work vehicle (100) can change the reference speed to the second speed if the condition of operation 630 is satisfied as a result of performing operations 610, 620, 630, and 640 based on the first speed. The agricultural work vehicle (100) can change the reference speed back to the first speed if the condition of operation 630 is satisfied as a result of re-performing operations 610, 620, 630, and 640 based on the reference speed changed to the second speed. The agricultural work vehicle (100) can change the reference speed to the third speed if the condition of operation 630 is satisfied as a result of re-performing operations 610, 620, 630, and 640 based on the reference speed returned to the first speed. The agricultural work vehicle (100) can repeat operations 610, 620, 630, and 640 based on the reference speed changed to the third speed. The agricultural work vehicle (100) can terminate operation 240 when correction is completed for all preset reference speeds. The current steering neutral value at that point becomes the steering neutral value that has finally been corrected.

[0092] The embodiments of the present disclosure described above may be implemented in the form of a recording medium comprising computer-executable instructions, such as program modules executed by a computer. A computer-readable medium may include any volatile and non-volatile media, and removable and inseparable media, that can be accessed by a computer. Additionally, a computer-readable medium may include computer storage media and communication media. A computer storage medium may include volatile and non-volatile, removable and inseparable media implemented by any method or technique for storing information, such as computer-readable instructions, data structures, program modules, or other data. A communication medium may include other data of modulated data signals, such as computer-readable instructions, data structures, or program modules.

[0093] The foregoing description of the present disclosure is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present disclosure. Therefore, all of the above descriptions should be understood as illustrative and not limiting. For example, a component described in a single form may be implemented in a distributed manner, and components described in a distributed manner may likewise be implemented in a combined manner.

[0094] The scope of the present disclosure is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalents thereof should be interpreted as being included within the scope of the present disclosure.

Claims

1. A step of obtaining a first measurement value corresponding to the forward direction of an agricultural work vehicle (100) using a direction sensor (120), and obtaining a second measurement value corresponding to a state in which the front wheels of the agricultural work vehicle (100) are centrally aligned by user operation using a steering angle sensor (130); A step of generating a reference path based on the first measurement value above; A step of obtaining the actual direction of movement of the agricultural work vehicle (100) while the agricultural work vehicle (100) is driving while following the reference path, and correcting a direction error based on the first measurement value and the actual direction of movement; and The method comprises the step of obtaining the actual travel path of the agricultural work vehicle (100) while the agricultural work vehicle (100) is driving while following the reference path, and determining a steering neutral value based on the second measurement value and the actual travel path. Method for correcting direction error and steering angle error of an agricultural work vehicle.

2. In Paragraph 1, The step of obtaining the second measurement value above is, A step of displaying a message on the HMI (140) instructing the user to operate the steering wheel to a neutral position, and A method comprising the step of obtaining a measurement value of the steering angle sensor (130) as the second measurement value when the steering wheel is operated to a neutral position by the user. Method for correcting direction error and steering angle error of an agricultural work vehicle.

3. In Paragraph 1, The step of obtaining the second measurement value above is, A step of displaying a message in the HMI (140) guiding the user to operate the steering wheel to the maximum rotation position of the first direction, either clockwise or counterclockwise, A step of obtaining a third measurement value of the steering angle sensor (130) when the steering wheel is operated to the maximum rotation position of the first direction by the user, A step of displaying a message on the HMI (140) guiding the user to operate the steering wheel to a maximum rotation position in the second direction opposite to the first direction, A step of obtaining a fourth measurement value of the steering angle sensor (130) when the steering wheel is operated to the maximum rotation position of the second direction by the user, and A step comprising obtaining the median of the third measurement value and the fourth measurement value as the second measurement value. Method for correcting direction error and steering angle error of an agricultural work vehicle.

4. In Paragraph 1, The above reference path is, A straight path from the current position of the agricultural work vehicle (100) toward the direction corresponding to the first measurement value, Method for correcting direction error and steering angle error of an agricultural work vehicle.

5. In Paragraph 1, The step of correcting the above-mentioned direction error is, A step of acquiring a plurality of first position measurements while driving while following the above reference path, A step of determining the actual direction of movement based on the plurality of first position measurements, A step of calculating a heading offset, which is the difference between the direction corresponding to the first measurement value and the actual direction of movement, and A method comprising the step of correcting the direction error by applying the direction offset to the measurement value of the direction sensor (120). Method for correcting direction error and steering angle error of an agricultural work vehicle.

6. In Paragraph 5, The step of determining the actual direction of movement based on the plurality of position measurements above is, Applying at least one algorithm among linear regression, moving average, Kalman filtering, or principal component analysis (PCA) to the above plurality of position measurements, or By calculating a vector determined by two of the above plurality of position measurements, Determining the actual direction of movement above, Method for correcting direction error and steering angle error of an agricultural work vehicle.

7. In Paragraph 1, After the step of correcting the direction error, the method further includes a step of returning to the original position via reverse to perform the step of determining the steering neutral value. Method for correcting direction error and steering angle error of an agricultural work vehicle.

8. In Paragraph 1, The step of determining the steering neutral value above is, A step of obtaining a plurality of second position measurements corresponding to the actual movement path while driving while following the reference path at a reference speed, A step of calculating the bias and oscillation of the lateral error between the actual movement path and the reference path based on the plurality of second position measurements above, A step of determining whether the magnitude of the deviation of the above lateral error is less than or equal to a first reference value and whether the shaking of the above lateral error is less than or equal to a second reference value, If the deviation of the lateral error is greater than a first reference value or the oscillation of the lateral error is greater than a second reference value, a step of adjusting the current steering neutral value based on the deviation and oscillation of the lateral error, and Based on the adjusted steering neutral value, the method includes the step of obtaining the plurality of second position measurements, the step of calculating the deviation and oscillation of the lateral error, and the step of repeating the step of determining whether the magnitude of the deviation of the lateral error is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value. Method for correcting direction error and steering angle error of an agricultural work vehicle.

9. In Paragraph 8, The step of adjusting the current steering neutral value mentioned above is, A step of determining the adjustment direction of the current steering neutral value based on the deviation of the above lateral error, and A step including determining the adjustment magnitude of the current steering neutral value based on the oscillation of the above lateral error, Method for correcting direction error and steering angle error of an agricultural work vehicle.

10. In Paragraph 8, The above reference speed is the first speed among a plurality of preset speeds, and The step of determining the steering neutral value above is, A step of determining whether the correction of the steering angle error is completed for all preset reference speeds if the magnitude of the deviation of the above lateral error is less than or equal to a first reference value and the shaking of the above lateral error is less than or equal to a second reference value. If the correction of the steering angle error has not been completed for all preset reference speeds, the step of changing the reference speed, and Based on the changed reference speed, the method further comprises the steps of: obtaining the plurality of second position measurements; calculating the deviation and oscillation of the lateral error; determining whether the magnitude of the deviation of the lateral error is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value; and repeating the step of adjusting the current steering neutral value. Method for correcting direction error and steering angle error of an agricultural work vehicle.

11. In Paragraph 10, The step of changing the above reference speed is, A step of changing the reference speed to a second speed different from the first speed among the preset multiple speeds, If the magnitude of the deviation of the lateral error calculated based on the reference speed changed to the second speed is less than or equal to the first reference value and the oscillation of the lateral error is less than or equal to the second reference value, the step of changing the reference speed back to the first speed; and If the magnitude of the deviation of the lateral error calculated based on the reference speed changed back to the first speed is less than or equal to a first reference value and the oscillation of the lateral error is less than or equal to a second reference value, the method includes the step of changing the reference speed to a third speed different from the first speed and the second speed among the preset plurality of speeds. Method for correcting direction error and steering angle error of an agricultural work vehicle.

12. In Paragraph 10, The step of determining the steering neutral value above is, The method further includes the step of terminating the step of determining the steering neutral value when the correction of the steering angle error for all preset reference speeds is completed. Method for correcting direction error and steering angle error of an agricultural work vehicle.

13. In an agricultural work vehicle (100), A direction sensor (120) for measuring the forward direction of the above agricultural work vehicle (100); A steering angle sensor (130) for measuring the steering angle of the above agricultural work vehicle; Memory (150) for storing one or more instructions; and It includes at least one processor (160), When the above one or more instructions are executed by the above at least one processor (160), the agricultural work vehicle (100) is, A first measurement value corresponding to the forward direction of the agricultural work vehicle (100) is obtained using the direction sensor (120), and a second measurement value corresponding to the state in which the front wheels of the agricultural work vehicle (100) are centrally aligned by user operation is obtained using the steering angle sensor (130). A reference path is generated based on the above first measurement value, and While the agricultural work vehicle (100) is driving while following the reference path, the actual direction of movement of the agricultural work vehicle (100) is obtained, and a direction error is corrected based on the first measurement value and the actual direction of movement. While the agricultural work vehicle (100) is driving while following the reference path, the actual travel path of the agricultural work vehicle (100) is obtained, and a steering neutral value is determined based on the second measurement value and the actual travel path. Agricultural work vehicle.

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