Work equipment

Abstract

To provide a work machine capable of resolving a position deviation from a proper travel line in line with a difference in a farm field or planting.SOLUTION: A work machine includes own vehicle position detection means attained by a position detector, determines a travel line oriented in an advancing direction 600 which is a target in a farm field, and autonomously travels while aligning an own vehicle position with the travel line. The work machine makes it possible to select one of a control mode in which a priority is given to a position deviation in position deviation control dependent on a distance 603 of a position deviation of the own vehicle position from the travel line and a control mode in which a priority is given to a direction deviation in direction deviation control dependent on an angle 604 of a direction deviation of an axle 610 from the travel line.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a farm implement that is capable of automatic straight-line travel with high accuracy in the agricultural field. [Background technology]

[0002] The invention is described as improving detection accuracy in automatic driving and dealing with deviations in detected position. There are two major types of deviations from the target line: deviation in distance and deviation in direction, and the invention prioritizes eliminating deviations in distance, i.e., eliminating deviations in position.

[0003] Therefore, although the degree of control was changed depending on the difference in the field or the difference in the crop, the control could only respond within a set range (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-164160 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional technology, position deviation control is initiated with a priority on eliminating position deviations, which are deviations in distance, and the steering angle is determined based on the degree of this deviation, so there are no restrictions on how to deal with deviations in direction. As a result, large steering is sometimes required, which makes it possible to minimize the area that remains unworked, but it can also cause the body of the work machine to tilt significantly relative to the driving line, which can cause damage to the field.

[0006] An object of the present invention is to provide a work machine that appropriately corrects positional deviation from the travel line in response to differences in farm fields and crops. [Means for solving the problem]

[0007]

[0008]

[0009] first The invention is solved by the following technical means.

[0010] The steering wheel and the wheels of the work vehicle are not mechanically linked; the steering angle is read by an angle detection device and the wheels are steered by electrical steering control. When steering rotation is detected while traveling on the driving line, steering control and steering settings are made according to the steering angle, and steering control of the wheels is performed until the steering angle reaches a first steering angle, and when the steering angle is rotated to a second steering angle, which is a larger steering angle, the system enters a control mode that prioritizes position deviation, and when the steering angle is rotated to a third steering angle, which is an even larger steering angle, the system enters a control mode that prioritizes directional deviation.

[0011] second The invention is solved by the following technical means.

[0012] In the configuration 9S-1 in which the steering wheel is rod-shaped, steering control of the wheels is performed up to a first tilt angle depending on the tilt angle of the steering wheel, and when the steering wheel is tilted to a second tilt angle, which is a larger tilt angle, the control to align the wheel with the driving line enters control that prioritizes position deviation control, and when the steering wheel is tilted to a third tilt angle, which is an even larger tilt angle, the control to prioritize azimuth deviation control is performed. [Effects of the Invention]

[0013] Book The invention allows the user to select whether to prioritize eliminating positional deviations or directional deviations.

[0014] Also By incorporating this control selection into the steering angle, the user can operate the car more easily. Also, since there is no steering vibration when driving in a straight line, the user does not feel fatigued due to vibration.

[0015] Also Even when the steering is rod-shaped, the user can select between positional deviation priority and directional deviation priority within the tilt angle, making operation easier. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a working machine with its exterior removed, according to an embodiment of the present invention; [Figure 2] FIG. 1 is an enlarged perspective view of a working machine with its exterior removed, according to an embodiment of the present invention; [Figure 3] 1 is a diagram showing the electrical system of a work machine according to an embodiment of the present invention; [Figure 4] Flow diagram of the straight-line assist control of the present invention [Figure 5] A diagram showing the relationship between steering operation and control contents of the present invention. [Figure 6] Movement diagram of the work machine when position deviation control is prioritized during two-wheel steering of the present invention [Figure 7] Movement diagram of the work machine when the directional deviation control is prioritized during two-wheel steering of the present invention [Figure 8] Movement diagram of the work machine when position deviation control is prioritized during four-wheel steering of the present invention [Figure 9] A diagram showing the relationship between the operation and control of the rod-shaped steering configuration of the present invention. [Figure 10] Flowchart for correcting GPS position coordinates [Figure 11] A view of the steering wheel and its surroundings according to the present invention. [Figure 12] Operation diagram of the steering actuator of the present invention [Figure 13] Engine installation diagram of the present invention [Figure 14] Schematic diagram of the difference between positional deviation priority and directional deviation priority in the present invention DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described below with reference to the embodiments shown in the drawings.

[0018] The working machine shown in FIGS. 1 to 14 is an example of the working machine of this embodiment.

[0019] The flow of power transmission in the present invention will be described.

[0020] As shown in Figures 1 and 2, inside the hood 110 at the front of the machine, there is a low-voltage battery 120 located in the left-right direction at the front of the machine body, a high-voltage main battery 130 located in the front-to-rear direction behind it, and an electric motor 140 located in the front-to-rear direction next to the main battery 130, which serves as a power source for operating the machine body and working equipment using the electricity from this main battery 130.

[0021] The low-voltage battery 120 serves as the power source for the driver's seat display 330 and the work machine controller 331. It is an auxiliary battery that is a controller that controls driving and work, communicates with external devices, and registers data on each operating state, and is a low-voltage battery such as a 12V battery. The low-voltage battery 120 is charged with regenerative electricity from the regenerative motor 550 using surplus power from the HST 150. The voltage of the high-voltage main battery 130 is managed by the MDU 131, which controls the electric motor 140.

[0022] The electric motor 140 is equipped with an external fan 141 at the rear end of the motor, which is linked to the motor shaft, and while the motor is operating, the wind generated by the external fan 141 cools the motor, low-voltage battery 120, and main battery 130. The heated wind is discharged to the outside through the grill mesh portion 111 at the front of the hood 110 and from the front lower part of the hood. The hood 110 completely covers the electric motor 140, low-voltage battery 120, and main battery 130, making it splash-proof against rain and when washing the car, and it is also moderately dust-proof.

[0023] As shown in Figure 2, the output shaft of the electric motor 140 is positioned at the rear of the vehicle in the longitudinal direction, and it supplies power to the HST 150 located behind it. The power transmission method may be to connect pulleys on each shaft with a belt, or the electric motor 140 may be directly connected to the HST shaft. In the case of belt drive, the shaft of the electric motor 140 and the input and output shafts of the HST 150 are parallel in axis, and as a power mechanism, power is transmitted in series without bending, which reduces loss and allows for a compact layout.

[0024] In Figure 13, the output shaft of the electric motor 140 is located at the rear of the vehicle body and connected to the HST 150, making it easy to achieve compatibility with the engine 650 configuration. By arranging the heavy main battery 130 and electric motor 140 on the hood 110 and making them similar in weight to the engine 650, a configuration is achieved in which there is no difference in balance between the electric motor 140 specifications and the engine specifications. By removing the BMS and inverter 160 from the hood 110 and arranging them behind the seat 170, it is possible to improve maintenance and address heat buildup. Even in this configuration, the low-voltage battery 120 is charged with regenerative electricity from the regenerative motor 550 using surplus power from the HST 150.

[0025] As shown in Figure 3, the BMS (Battery Management System) manages the high-voltage main battery 130, receiving commands from the control unit 180 and performing voltage management according to the controls. The inverter located in the same position is also called the MDU and controls the rotation speed of the electric motor. In this proposal, the BMS and inverter 160 are integrated and placed behind the seats for easy maintenance, and are also able to deal with heat buildup and dust. Depending on the configuration, the BMS and inverter (MDU) may be placed in separate locations.

[0026] With this arrangement, the electric motor 140 can rotate continuously at a fixed rotation speed, or it can be inverter controlled so that the rotation speed can be varied according to the required power. In this embodiment of the present invention, the system controls the rotation speed of the electric motor 140 in response to commands from the control unit 180 of the machine, while managing the high-voltage main battery 130 via the BMS and inverter 160. Because of this system, even when the machine stops traveling and the work equipment is also stopped, the rotation speed of the electric motor 140 decreases within the range in which the reference hydraulic pressure of the HST 150 can be generated.

[0027] The basic positional deviation response and automatic steering of the robotic work machine 100 will now be described.

[0028] The GPS receiver 310 and the positioning unit, which is the positioning method, are composed of a mobile station installed in a positioning satellite and a base station installed in a known location. This makes it possible to accurately obtain the position of the mobile station, i.e., the position of the work equipment, from the position information sent from the positioning satellite to the mobile station and the correction position information sent from the base station to the mobile station.

[0029] The base station is made up of a fixed communication device, a GPS receiver 310 that receives position information from positioning satellites, and a fixed data transmission antenna that transmits corrective position information to the mobile station.

[0030] The mobile station is composed of a mobile communication device, a mobile GPS receiving device that receives position information from positioning satellites, and a mobile data transmission antenna that receives position information for correction from a base station. The control unit 180 of the work machine is composed of a processing unit consisting of a CPU etc., a storage unit consisting of ROM, RAM, a hard disk drive, flash memory etc., and a communication unit for data communication with the outside.

[0031] The GPS receiver 310 may use a method suitable for the area where work is being performed, such as a point positioning method, a differential GPS (DGPS) method, or a real-time kinematic (RTK) method. However, if the height above ground of the GPS receiver 310 fluctuates due to the tilt or vibration of the robot body, the measured coordinate position may differ from the actual robot body position, reducing reception accuracy and causing the robot to travel in a direction that deviates from a straight line. To prevent this, an inertial measurement unit (IMU) 320 is provided in addition to the GPS receiver 310. The inertial measurement unit (IMU) 320 causes the control unit 180 to correct the position coordinates acquired by the GPS receiver 310 based on the difference between the height from the ground surface to the GPS receiver 310 when the robotic work machine 100 is tilted and the height from the ground surface to the GPS receiver 310 when it is not tilted.

[0032] The height from the ground to the GPS receiver 310 is calculated by measuring the tilt and other behavior of the robotic work machine 100 using a triaxial acceleration sensor and angular velocity sensor built into the inertial measurement unit IMU 320. In addition, a direction sensor 311 is provided to enable the control unit 180 to more reliably determine whether the direction of travel of the robotic work machine according to the automatic straight-line driving system is correct. The correction of position coordinates at this time is as shown in SS1 to SS5 in Figure 10. This allows the robot's path to be determined by the measured direction, further improving the accuracy of straight-line driving.

[0033] The position information acquired by the GPS receiver 310 is corrected by the control unit 180 based on information detected by the inertial measurement unit IMU 320 and the direction sensor 311. The control unit 180 then compares the current position information with previously acquired position information, and if the difference between the position information exceeds an allowable range, steers the left front wheel 560 and the right front wheel 570 left and right to return the aircraft to a straight-ahead driving position.

[0034] In order to automate the steering of the left front wheel 560 and the right front wheel 570, an automatic steering device 172 is provided that rotates a steering wheel 171 shown in Fig. 11 using a steering actuator 173. The automatic steering device 172 turns the steering wheel 171 left or right to direct the vehicle toward a straight-ahead driving position by varying the amount of operation of the steering actuator 173 based on the difference between the X coordinate of the current position information calculated by the control unit 180 and the X coordinate of the reference position information previously acquired, as shown in SS6 to SS9 in Fig. 12, and when the vehicle reaches the straight-ahead driving position, stops the steering actuator 173 to stop the automatic steering 172 of the steering wheel 171.

[0035] The steering actuator 173 is composed of an electric or hydraulic motor or cylinder. With the above configuration, the steering 171 is automatically steered in accordance with the difference in the X coordinate of the calculated position information, and the machine body can be automatically aligned to a straight-ahead driving position, preventing the working position of the working device from shifting left or right, and making it less likely that areas in the field will not be worked on. This eliminates the need to manually work on areas that were not worked on later, reducing the labor required by the worker.

[0036] This section explains the vehicle position and inertial coordinates calculated by the GPS receiver and inertial measurement unit.

[0037] The robotic work implement 100 is controlled to superimpose the coordinates of the GPS receiver 310 onto the coordinate position of its own vehicle, with east-west as the X axis and north-south as the Y axis. The system also acquires the coordinates of one side of the field, which is the starting point of the robotic work implement 100's automatic straight-line movement, and the other side of the field, which is the end point of the automatic straight-line movement.

[0038] After first reference point A601 is acquired, second reference point B602 is acquired, and this straight line becomes the traveling direction 600. If the front and rear axles 610 of the vehicle, so-called direction lines, are inclined with respect to the driving line heading toward the traveling direction 600, a direction change is performed as shown in FIG.

[0039] The first reference point A601 and the second reference point B602 are relocated and set at predetermined positions at one end and the other end of the field, for example, the position where the implement finishes traveling straight and starts turning, and the position where the implement starts traveling straight after turning, and then the implement travels straight.

[0040] As described above, when the first reference point A601 and the second reference point B602 are newly acquired, the reference line connecting the Y coordinates of the first reference point A601 and the second reference point B602 becomes the relocated and set reference line for automatic straight-line driving. The system determines whether the X coordinate of the vehicle's position coordinates during travel matches the X coordinate of the reference line for automatic straight-line driving. If they do not match, the automatic steering device 172 automatically steers the steering wheel 171 in the direction that matches, thereby achieving automatic straight-line driving. The control unit 180 compares the Y coordinate of the position coordinates acquired by the GPS receiver 310 with the Y coordinate of the reference line, and activates the steering actuator 173 to rotate the steering wheel 171 left and right, thereby starting control to move the robotic work machine 100 to a position where it should travel straight. This automatic steering ends when the steering wheel 171 is operated to an angle that turns the traveling vehicle body within a predetermined time, or when the automatic straight-line setting member 207 is operated in the second direction. The steering angle of the steering wheel 171 is detected by a handle potentiometer 172. When the traveling vehicle body 2 reaches a location that matches the Y coordinate of the first reference point A or the second reference point B, the automatic straight-line control may be terminated and turning control may be initiated.

[0041] In this embodiment, the position information of the reference line is acquired for each work process, and the position information of the target line for the next work process is determined for each work process. This minimizes the deviation of the reference line, reduces the deviation of the target line for the next work process, and also enables alignment in the automatic turning process.

[0042] Furthermore, when setting the target line for the next process, in order to avoid leaving untreated areas such as residual tillage, it is necessary to leave an overlap, or so-called overlap, rather than shifting the target value position by the width of the implement in the next process. However, if the overlap is too large, the work area will be larger than the field area, resulting in work loss. Therefore, during automatic operation, the overlap is set to a minimum to eliminate untreated areas and increase work efficiency.

[0043] Specifically, one method is to set the AB points of the next process at a value 10 cm shorter than the width of the work machine and determine the driving line, or to determine the value by multiplying a safety factor based on the minimum radius when turning.

[0044] By controlling the overlap, a driving line is determined that will not leave any untreated areas, but the reference line may shift over time or may shift due to the influence of clouds, etc. Therefore, by obtaining a new reference line for each work process as described above, it is possible to minimize shifts in the reference line, and the deviation of the target line in the next planting work process can also be reduced, and by controlling the overlap each time, row alignment can also be performed in the automatic turning process.

[0045] Four-wheel drive and four-wheel steering driving will now be described.

[0046] This work machine is four-wheel drive and allows for four-wheel steering. It is equipped with a front left wheel 560, a front right wheel 570, a rear left wheel 580, and a rear right wheel 590. Each wheel (560, 570, 580, 590) receives power from the same HST150 and rotates, but the power transmission path allows for individual speed changes to each axle, and the rotation speed can be changed individually using the planetary gears in the final case of each wheel. The brakes on each wheel can also be applied individually using electronic control.

[0047] Each wheel can be steered by an individual link. In the present invention, each axle is provided with an individual electric gear motor, and its rotation is controlled by the control unit 180. Each axle is provided with a potentiometer to detect the steering angle individually. If the detected angle differs from the steering angle commanded by the control unit 180, the respective electric gear motor is operated.

[0048] By using the controls, it is possible to drive in two-wheel drive with two-wheel steering or four-wheel drive with two-wheel steering, making it a versatile work machine. The driving instructions also include the contents of dedicated vehicles for two-wheel drive with two-wheel steering and four-wheel drive with two-wheel steering.

[0049] 6 to 8 show an embodiment of the first invention.

[0050] As shown in Figure 6, a first reference point A601 and a second reference point B602 are acquired, and a driving line in a direction 600 is determined. The vehicle position calculated by the GPS receiver and the inertial measurement unit is in inertial coordinates.

[0051] In automatic driving or straight-line assisted driving, the position detected by the inertial coordinates, the position based on the driving line obtained by acquiring the first reference point A601 and the second reference point B602, and the position of the vehicle calculated by the GPS receiver and the inertial measurement device are controlled to be aligned with the direction of travel 600 while aligning the front and rear axles 610 with the direction of travel 600.

[0052] FIG. 6 shows a case where the heading is the same with respect to the traveling direction 600, but the vehicle center position 611 is not on the traveling line of the traveling direction 600 and is therefore misaligned. In the prior art, the misalignment distance 603 is adjusted while traveling. Therefore, even if the headings match, the heading change is permitted and the heading is changed within a predetermined range to adjust the misalignment, and the misalignment is gradually adjusted while traveling. After performing this alignment, the heading is adjusted. This control that prioritizes the misalignment is called position deviation priority.

[0053] Position deviation priority is a control that steers the tractor away from the direction of travel 600 even if the direction of travel 600 matches or is close to the travel line, as shown in Figure 6. This makes it possible to quickly correct the misalignment and reduce the untilled area, but the large steering can damage the field. In this case, a direction deviation angle 604 occurs.

[0054] Depending on the user's operating conditions and the conditions of the field, it may not be desirable to uniformly prioritize positional deviation. Conventional technology addresses such cases by determining a maximum steering angle and restricting steering. Alternatively, there is control that sets a positional deviation elimination rate based on travel distance or travel time, and steers within that range. However, in either type of control, a reference value is set in advance, and the strength of positional deviation elimination is set within that range, and the directional deviation angle 604 is determined based on the degree of elimination. Therefore, these controls are not suitable for controlling directional deviation, such as driving straight within a certain range.

[0055] In order to solve this problem, the present invention takes into consideration the case where directional deviation priority is desired and provides a mechanism that allows the user to select between position deviation priority and directional deviation priority. Furthermore, this switching mechanism is not performed by a selector switch on the operation panel, but by incorporating it into the degree of steering angle, allowing the user to operate safely, easily, and without operating errors while driving.

[0056] The directional deviation priority setting will be explained with reference to FIG. 7. The traveling direction 600 is correct, but the positional deviation from the traveling line is large. With the positional deviation priority setting in FIG. 6, the steering angle is turned large, and the axle 610 of the work machine is tilted significantly relative to the traveling line. However, with the directional deviation priority setting in FIG. 7, the steering angle is small, and the angle between the axle 610 of the work machine and the traveling line, or directional deviation angle 604, is small, and it can be seen that the vehicle travels almost straight within a set range. With this directional deviation priority setting, the angle between the axle 610 of the work machine and the traveling line, or directional deviation angle 604, is fixed at a set value when traveling. Therefore, the steering angle is controlled to gradually decrease from the initial steering angle. In a farm field, if the user is aware of the initial steering slippage, the steering angle will not increase any further. This allows for safe automatic driving without worrying about damaging the field.

[0057] Position deviation is also detected, and steering control is performed using PID control including this value.

[0058] In Figure 7, the central diagram shows a state where the position deviation has approached a predetermined range. Because the steering angle is gradually reduced, the steering angle is gradually reduced until it finally reaches 0, and the axle 610 and the driving line match in both position and direction. However, if the driving speed is high or the field is soft and slippery, when aligning the axle 610 with the driving line, reverse steering may be performed to match the vehicle direction, and steering control is performed while sensing the vehicle speed using PID control.

[0059] Figures 6 and 7 are based on two-wheel drive two-wheel steering driving, but Figure 8 shows four-wheel drive four-wheel steering driving. In this case, parallel movement driving is possible using four-wheel steering, so even if directional deviation is prioritized, the direction will match. The initial steering angle is determined based on the position deviation, and by gradually reducing it, the position deviation is eliminated.

[0060] In this way, in a work machine with four-wheel steering function, if the angle between the axle 610 and the driving line is the same, or even if it is detected at the beginning of operation, it can be resolved early, so the control is centered on control of position deviation and steering angle, which is a PID control that is different from two-wheel steering driving.

[0061] The control contents of positional deviation priority and directional deviation priority have been shown, and the control within the controller for both controls will be explained while describing the contents of selecting between these two controls.

[0062] 4 is a control flow diagram of the first invention. The work machine has position information S4-1 from satellite information, information S4-2 of the pre-set A and B lines of the travel lines 601 and 602, and, depending on the work machine, means S4-3 for calculating position information from cloud information and captured images using imaging means. Straight-line driving assistance is started based on this information.

[0063] Straight-line assist operation S4-4 is automatic driving. In the standard setting, straight-line assist control performs position deviation calculation S4-7. In other words, the control prioritizes eliminating position deviation. This standard limits the range of the steering angle. Within that range of steering angle, the steering angle is determined by PID control according to the amount of position deviation and vehicle speed.

[0064] In PID control, P is proportional, I is integral, and D is differential. The integral of I is calculated using 1 / integral time, and the differential of D is calculated using differential time. The proportional gain is calculated by correcting the proportional value of P. Table data and reference conversion are then performed based on the calculated proportional gain to calculate the degree of steering angle strength. These calculations result in target direction calculation S4-8 and direction deviation calculation S4-9. If the result is within a reference range, steering angle calculation S4-10 is calculated, and automatic steering S4-11 is performed based on this value.

[0065] Steering control continues until the target value is reached, as in S4-12. However, if the user operates the steering wheel and a manual steering signal is detected, as in S4-13, the standard automatic driving is canceled. The control content can be changed depending on how far the steering angle is turned within a specified time.

[0066] This is just one example of a switching means, but it is also possible to provide a switch for switching between position deviation priority and directional deviation priority in the operation panel, so that by switching the switch it is possible to switch between position deviation priority S4-17 and directional deviation priority S4-19, as in S4-16. Whatever switching means is used, the object of the present invention is to be able to switch between position deviation priority and directional deviation priority.

[0067] Position deviation priority and direction deviation priority calculate both position and direction to calculate the steering angle S4-18, S4-20, but do not mean that one item is not calculated. They change which calculation formula is given priority for the proportional gain value of PID control.

[0068] Furthermore, when position deviation priority or directional deviation priority is selected, the setting for selecting the degree of change in steering angle is entered, and it is possible to select the degree. In the present invention, these are selected by the magnitude of the steering angle, and when this angle is maintained for a predetermined time, it is registered as a setting. Once determined, it will continue unless it is reset, the release switch is pressed, or the engine is stopped.

[0069] Finally, the position information is confirmed using GPS etc., and S5-21 is checked to see if the target position has been reached. In this way, if the steering is used to select position deviation priority or directional deviation priority and the degree of priority is set, and if it is confirmed in S4-21 that there are no problems with control, the automatic driving change setting is registered as in S4-22.

[0070] As mentioned above, the system is released when S4-13 detects a signal from the steering wheel during straight-line assist driving. Alternatively, the system is reset by manually pressing the release switch or by stopping the engine, and returns to the standard S4-7 control.

[0071] The difference between position-priority control and direction-priority control will be further explained with reference to Fig. 14. S14-1 to S14-6 are the flow of position-priority control, and S14-7 to S14-12 are the flow of direction-priority control.

[0072] If position priority control is set, a position deviation calculation S14-2 is performed. This is the value of the distance difference between the target driving line and the vehicle's position calculated by GPS. Position deviation control allows the setting of the position deviation elimination speed S14-3, which, as described in the second invention, can be set by the steering angle. The setting can be set in several stages, but here three stages are shown: slow, normal, and fast. This setting indicates the degree to which the distance difference, which is the position deviation, can be reduced per unit time. For example, slow corresponds to 0.2 m / s, normal corresponds to 0.4 m / s, and fast corresponds to 0.6 m / s. In S14-4, the target vehicle direction and target direction are calculated based on the vehicle speed and position deviation elimination speed. However, if a direction deviation is calculated as in S14-5, a check is made to ensure that the direction change does not exceed the set limit. This control is used to calculate the steering angle in S14-5, and the PID control prioritizes position deviation.

[0073] PID control is shown in the schematic diagram of S14-13, with P: proportional (S14-14), I: integral (S14-15), and D: differential (S14-16) as described above. This PID control is the same whether position deviation priority is given or directional deviation priority is given, but the coefficient of Kp: proportional gain (S14-17) is different, and the calculated value of the steering angle differs depending on whether position change priority is given or directional change priority is given.

[0074] In this way, the steering angle is calculated and steering control S14-19 is performed, but if the vehicle position is calculated from GPS position information S14-18 and the control content is not as targeted, automatic steering control correction is applied in S14-20 to correct position and direction deviations.

[0075] If directional priority control is set, directional deviation calculation S14-18 is performed. This prioritizes control of the angle between the target driving line and the axle 610. Directional deviation control allows the setting of a directional deviation angle limit range S14-9. As described in the second aspect of the invention, this can be set by the steering angle. The setting can be set in several stages, but here, three stages are shown: no large directional deviation, allowable directional deviation within a normal range, and allowable directional deviation up to a maximum setting. This setting determines how large the angle between the target driving line and the axle 610 should be. For example, when no large directional deviation is set, the vehicle is gradually aligned within an angle of 5 degrees. When allowable directional deviation within a normal range, the angle is set to 10 degrees. When the direction is changed up to the maximum setting, the angle is set to 40 degrees or less. Target position calculation is performed in S14-10. However, when the position deviation is calculated as in S14-11, a check is made to ensure that it does not fall within the set limit of position change amount. In this case, the limit value for when the position deviation cannot be eliminated is confirmed. This control is used to perform the steering angle calculation in S14-12, and the PID control that prioritizes the directional deviation is used.

[0076] The PID control is the same as that described above in S14-13 to S14-16. As described above, the coefficient of Kp (proportional gain) S14-17 is changed, and the calculated value of the steering angle differs between position change priority and direction change priority. The contents of S14-18 to S14-20 are the same as those described above.

[0077] The steering operation of the second invention will now be described. In the control flow of Fig. 4, S4-13, S4-14, S4-15, S4-16, and S4-19 are linked to the steering angle.

[0078] FIG. 5 is a diagram showing the steering angle. S5-1 is the reference position, which indicates straight driving. In this invention, the steering angle is detected electrically by a rotary encoder, and there is no mechanical interlocking. Therefore, in automatic driving such as straight-line assist, the steering wheel does not rotate or vibrate and remains fixed. Therefore, even if the user holds the steering wheel firmly while driving straight, they are not subjected to steering wheel vibrations, allowing them to drive safely and without fatigue.

[0079] The first steering angle ranges of S5-2 and S5-10 are within the range for manual steering. Turning the steering wheel to the left or right within each range from S5-1 enables manual steering, and the larger the steering angle, the larger the steering angle. The response of the initial steering angle is made somewhat slow to deal with the case of a malfunction. If the steering wheel returns to the reference position instantly, the control will not enter manual control, position deviation priority, or directional deviation priority. Conversely, if the steering wheel is turned and a predetermined time has not passed, the control will not enter manual control, position deviation priority, or directional deviation priority, resulting in a sluggish response.

[0080] The second steering angle, S5-3 and S5-11, are steering positions that prioritize position deviation control. Control is accepted once the steering is turned to this angle and a predetermined time has passed. There are degrees of position deviation control, with S5-4 and S5-12 resulting in weaker changes to the steering angle, while turning the steering to S5-6 and S5-13 allows for stronger settings. In either case, when the steering is fixed at the desired angle for a predetermined time, the settings are registered and will remain in effect until they are reset, the release switch is pressed, or the engine is stopped.

[0081] The third turning angle, S5-7 and S5-14, are steering positions that prioritize directional deviation control. Control is accepted after turning to this angle and a predetermined time has passed. There are degrees of directional deviation control, with S5-8 and S5-14 resulting in weaker changes to the steering angle, while turning the steering to S5-9 and S5-16 allows for stronger settings. In either case, when the steering is fixed at the desired angle for a predetermined time, the setting is registered and will remain in effect until it is reset, the release switch is pressed, or the engine is stopped.

[0082] The third invention will now be described. Figure 9 shows the configuration when the steering is a rod-shaped joystick lever. A similar configuration can also be applied to power steering levers in crawler-type work machines such as combine harvesters. This lever responds by detecting the degree and angle of tilt when tilted left or right.

[0083] Like other implements such as combine harvesters, the implement of the present invention uses a dedicated lever to adjust the travel direction and speed. The reaping section of the implement can be raised and lowered by moving this lever to the center of S9-1.

[0084] An example in which the steering is rod-shaped will be described. Within the first tilt angle range of S9-2 and S9-5, the steering wheel comes into contact with a resistant stopper. This left and right tilt angle is used for manual steering. The steering degree can be changed by the crawler operating time, and the system steers for the time period shifted from S9-1 to S9-2 and S9-5.

[0085] Once the second tilt angle, S9-3 and S9-6, has been reached and a predetermined time has elapsed, position deviation priority control will be entered. Once this control is entered, the forward / backward control of the lever will be exclusively for the setting mode of position deviation degree control. The degree will be higher when tilted forward, and lower when tilted backward. In both cases, the degree differs depending on the forward / backward tilt angle, and is set and registered by fixing it for a predetermined time.

[0086] Once the third tilt angle, S9-4 and S9-7, has been reached and a predetermined time has elapsed, directional deviation priority control will be entered. Once this control is entered, the forward / backward control of the lever will be exclusively for the setting mode of directional deviation degree control. The degree will be higher when tilted forward, and lower when tilted backward. In both cases, the degree differs depending on the forward / backward tilt angle, and is set and registered by fixing it for a predetermined time.

[0087] The first invention increases convenience through the second and third operations, and although it is possible to use other operating means, by incorporating them into the steering wheel or lever that is operated, safety and operability can be improved. [Explanation of symbols]

[0088] 100 Robotic Work Machine 120 Low voltage battery 130 High voltage main battery 140 Electric Motor 150 HST 160 BMS and inverter 310 GPS receiver 320 Inertial Measurement Unit IMU 600 Direction of travel 601 1st reference point A 602 2nd reference point B 610 front and rear axles S4-14 Steering control selection S4-17 Position deviation priority control S4-19 Directional deviation priority control S4-15 Manual operation control S14-3 Position deviation elimination speed (steering setting value) S14-9 Directional deviation limit range (steering setting value) S14-13 PID control

Claims

1. In a work machine that automatically travels while determining a travel line in a target traveling direction (600) in a field and aligning its own vehicle position with the travel line, the following is provided: Position deviation control based on the distance (603) of the positional deviation between the driving line and the vehicle position; In the directional deviation control based on the angle (604) of the directional deviation between the running line and the axle (610), a control mode is provided in which the position deviation is prioritized and the directional deviation is prioritized; The steering and wheels of the work vehicle are not mechanically linked. The steering angle is read by an angle detection device, and the wheels are steered by electrical steering control. When the steering wheel rotation is detected while the vehicle is traveling on the driving line, the steering control and steering setting are performed according to the steering angle, The steering control is performed up to the first steering angle, and when the steering angle is increased to the second steering angle, the control mode prioritizes position deviation. When the steering angle is turned to a third angle, which is an even larger angle, the work machine enters a control mode that prioritizes directional deviation.

2. A work machine that automatically travels while determining a vehicle position detection means using a position detection device, a driving line toward a target traveling direction (600) in a field, and aligning its own vehicle position on the driving line, Position deviation control based on the distance (603) of the positional deviation between the driving line and the vehicle position; In the directional deviation control based on the angle (604) of the directional deviation between the running line and the axle (610), a control mode is provided in which the position deviation is prioritized and the directional deviation is prioritized; In a configuration (9S-1) in which the steering is rod-shaped, the steering control of the wheels is performed up to a first tilt angle depending on the angle of the steering, and when the steering is tilted to a second tilt angle, which is a larger angle, the control enters control that prioritizes position deviation control in the control to align the wheels with the driving line, and when the steering is tilted to a third tilt angle, which is an even larger angle, the control enters control that prioritizes azimuth deviation control.

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