Work vehicles

Abstract

In work vehicles, the reference position for automatic straight-line driving is appropriately set, and the vehicle is less susceptible to changes in its attitude and direction of travel, thereby improving the accuracy and safety of automatic straight-line driving. [Solution] The system includes a steering member for steering the aircraft, a position information acquisition device, an IMU, a control device that calculates position coordinates using the IMU's detection results as an auxiliary basis for the position information, an automatic straight-line driving device, and a first operating tool for turning the device on and off. The control device records position coordinates calculated at different points in the field as a first reference position and a second reference position, and when the automatic straight-line driving is "on" and the first operating tool is operated, the automatic straight-line driving is turned "off".

Description

Technical Field

[0001] The present invention relates to a work vehicle that travels in a field and performs ground operations with a work device mounted on a traveling vehicle body.

Background Art

[0002] Some conventional work vehicles are equipped with an automatic steering device that acquires the position information of the work start position and the work end position when the work device is turned on and off, creates a reference line from the acquired work start position and work end position, automatically steers the steering wheel along this reference line, and makes the vehicle body travel straight. (Patent Document 1)

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The work vehicle described in Patent Document 1 can acquire the position where the work device is turned on and off as the work start position and the work end position. Therefore, there is no need to perform an operation to acquire the work start position and the work end position, and it has the advantage of good operability.

[0005] However, in a work vehicle that performs automatic straight running, the running accuracy may decrease due to the setting of the reference position and changes in the vehicle body posture and traveling direction during automatic straight running.

[0006] An object of the present invention is to provide a work vehicle that solves the above problems and improves the accuracy of automatic straight running by appropriately using the information used for acquiring the reference position and automatic straight running.

Means for Solving the Problems

[0007] The invention described in claim 1 comprises a steering member (35) for steering the aircraft, A position information acquisition device (200) that acquires the position information of the aircraft, The IMU mounted on the aircraft, A control device (100) calculates the aircraft's position coordinates using the detection results of the IMU as a supplement to the position information acquired by the position information acquisition device (200), An automatic straight-line driving device (205) that operates the steering member (35) to cause the aircraft to travel in a straight line, First operating device for switching the automatic straight-line device (205) on and off In a work vehicle equipped with, The control device (100) records position coordinates calculated at least based on position information acquired by the position information acquisition device (200) at different points in the field as a first reference position (A) and a second reference position (B). The work vehicle is characterized in that, with the first reference position (A) and the second reference position (B) recorded, and the automatic straight-line driving by the automatic straight-line device (205) being "on", when the first operating tool is operated, the automatic straight-line driving by the automatic straight-line device is "off".

[0008] The invention described in claim 2 is a work vehicle according to claim 1, characterized in that when the control device (100) records the first reference position (A) and the second reference position (B), it calculates the position coordinates using the detection result of the IMU in addition to the position information acquired by the position information acquisition device (200).

[0009] The invention described in claim 3 is a work vehicle according to claim 1 or 2, wherein the work vehicle further comprises an orientation sensor for detecting the orientation of the machine, and the control device (100) calculates the position coordinates using the position information acquired by the position information acquisition device (200), the detection result of the IMU, and the detection result of the orientation sensor when recording the first reference position (A) and the second reference position (B).

[0010] The invention described in claim 4 is a work vehicle according to claim 3, characterized in that the control device (100) controls the movement of the machine using the position information acquired by the position information acquisition device (200), the detection result of the IMU, and the detection result of the direction sensor while the machine is moving in a straight line by the automatic straight-line device (205).

[0011] The invention described in claim 5 is a work vehicle according to any one of claims 1 to 4, further comprising a second operating device for acquiring a reference position, wherein the second operating device is a push-button switch, and the control device (100) records the position coordinates as the reference position when the push-button switch is operated for less than a predetermined time, and deletes the recorded reference position when the push-button switch is operated continuously for a predetermined time or longer. [Effects of the Invention]

[0012] The invention of claim 1 allows for the automatic straight-line driving to be turned off based on the operation of the first operating device when the automatic straight-line driving is "on" with the first and second reference positions recorded. This prevents the automatic straight-line driving from being inappropriately continued during turning or driving at the edge of the field, thereby improving driving safety and work accuracy.

[0013] The invention of claim 2, in addition to the effects of the invention of claim 1, is configured to calculate position coordinates using the IMU detection results in addition to position information when recording the first reference position and the second reference position. This reduces the influence of aircraft tilt and attitude changes, and improves the accuracy of setting the reference position.

[0014] The invention of claim 3, in addition to the effects of the invention of claim 1 or 2, is configured to use the detection result of the orientation sensor in addition to the position information and the detection result of the IMU when recording the first reference position and the second reference position. This makes it possible to calculate position coordinates that take into account the direction of travel of the aircraft, and reduces directional errors between reference positions.

[0015] According to the invention of claim 4, in addition to the effects of the invention of claim 3, during automatic straight running, a configuration is adopted in which running control is performed using position information, the detection results of the IMU, and the detection results of the azimuth sensor. Therefore, the aircraft is less likely to be affected by vibrations, tilts, and attitude changes of the fuselage, and the stability of automatic straight running can be improved.

[0016] According to the invention of claim 5, in addition to the effects of the invention of any one of claims 1 to 4, a push button switch is used as the second operating tool for acquiring the reference position, and the reference position is recorded and deleted according to the difference in operation time. Therefore, the reference position can be managed without increasing the number of operating tools, and the operability can be improved and misoperations can be prevented.

Brief Description of the Drawings

[0017] [Figure 1] Side view of the seedling transplanter [Figure 2] Plan view of the seedling transplanter [Figure 3] Principal part plan view of the traveling vehicle body [Figure 4] Principal part rear view of the control part including the handle [Figure 5] (a) Principal part rear view showing the configuration of the automatic steering device of the handle, (b) Principal part side view showing the configuration of the automatic steering device of the handle [Figure 6] Block diagram showing members related to various controls [Figure 7] Flowchart showing control for correcting the acquired position coordinates according to the tilt of the fuselage, etc. [Figure 8] Flowchart showing automatic straight running control by the automatic steering device [Figure 9] Flowchart showing the acquisition of the first and second reference positions by operating the automatic straight running setting member and the on / off of the automatic straight running control [Figure 10] Flowchart showing the deletion operation of the first reference position and the second reference position [Figure 11] Flowchart showing control for deleting the first reference position by operating the handle after acquiring the first reference position [Figure 12]A schematic diagram of the operation showing the first reference position, second reference position, reference line, and target position. [Figure 13] A flowchart illustrating the activation of the warning device and the automatic deceleration control that occurs when the automatic steering system is not deactivated after the warning device is activated. [Figure 14] A flowchart illustrating the control process for erasing the first reference position, second reference position, and reference line by driving along the headland of the field. [Best Mode for Carrying Out the Invention]

[0018] Embodiments of the present invention will be described with reference to the drawings.

[0019] In this case, in the plan view, the left side of the aircraft relative to the direction of travel will be referred to as one side of the aircraft, and the right side of the aircraft relative to the direction of travel will be referred to as the other side of the aircraft. The details of each part will be described below.

[0020] As one embodiment of the implement of the present invention, the ride-on type rice transplanter disclosed in Figure 2 has an 8-row planting configuration, but this configuration may be used for rice transplanters with a different number of planting rows. As shown in Figures 1 and 2, the present rice transplanter has a lifting link device 3 on the rear side of the traveling body 2 that allows a seedling planting section, which takes seedlings from a seedling tank 53 and plants them in the field using multiple seedling planting devices 55..., a seeding device that supplies seeds, and an implement 4 such as a rotary tiller for cultivating the field to be raised and lowered, and the main body of a fertilizer applicator 5 is positioned on the upper rear side of the traveling body 2.

[0021] First, let's explain the main frame 15 that makes up the vehicle body 2.

[0022] As shown in Figure 3, the main frame 15 includes a front beam frame 16 at the front of the aircraft body, a rear beam frame 17 at the rear of the aircraft body, and a central beam frame 18 between the front and rear of the front beam frame 16 and the rear beam frame 17. The front beam frame 16 and the central beam frame 18 are connected by a pair of left and right front connecting frames 19, 19, and the central beam frame 18 and the rear beam frame 17 are connected by a pair of left and right rear connecting frames 20, 20.

[0023] The front beam frame 16, the central beam frame 18, and the rear beam frame 17 have their longitudinal direction in the left-right direction, while the front connecting frame 19 and the rear connecting frame 20 have their longitudinal direction in the front-back direction.

[0024] The left and right front connecting frames 19,19 and the rear connecting frames 20,20 are spaced approximately the same apart. Furthermore, the left-right lengths of the central beam frame 18 and the rear beam frame 17 are longer than the left-right lengths of the front beam frame 16. Since the left and right front connecting frames 19,19 and the rear connecting frames 20,20 are welded to the lower part of the central beam frame 18, the left and right front connecting frames 19,19 and the rear connecting frames 20,20 may be constructed from a single piece of metal.

[0025] The space formed by the front beam frame 16, the central beam frame 18, and the left and right front connecting frames 19, 19 is provided with a transmission case 13 that transmits driving force to the left and right front wheels 10, 10 and rear wheels 11, 11, work equipment 4, etc., and a hydraulic continuously variable transmission (HST) 14 that outputs driving force supplied from the engine 30 to the transmission case 13.

[0026] Then, left and right lifting frames 21, 21 are provided at the rear of the rear beam frame 18 at a distance narrower than the left and right distance between the left and right rear connecting frames 20, 20 and projecting to the rear, and a rear support frame 22 is attached to the lower part of the left and right lifting frames 21, 21. Rear wheel transmission cases 11a, 11a that drive the left and right rear wheels 11, 11 of the vehicle body 2 are provided on both the left and right sides of the rear support frame 22, and left and right link frames 23, 23 that support the lifting link mechanism 3 are provided facing upward on the upper part of the rear support frame 22.

[0027] The lifting link mechanism 3 is configured by providing a pair of left and right lower link arms 24, 24 on the lower side of the left and right link frames 23, 23 and between them, providing a lifting cylinder 25 between the left and right lower link arms 24, 24, and providing an upper link arm 26 above the lifting cylinder 25. The ends of the left and right lower link arms 24, 24, the lifting cylinder 25, and the upper link arm 26 opposite to the vehicle body 2 are attached to the front side of the work device 4.

[0028] Furthermore, front transmission cases 10a, 10a are provided at the front of both left and right ends of the central beam frame 18 and on the left and right outer sides of the left and right front connecting frames 19, 19, respectively, to transmit power to the left and right front wheels 10, 10 of the vehicle body 2. The left and right ends of the central beam frame 18 and the rear beam frame 17 are connected by left and right extension frames 27, 27, respectively. The left and right extension frames 27, 27 are oriented longitudinally in the front-rear direction.

[0029] Furthermore, a central connecting frame 28 is provided in the front-to-rear direction at the lower part of the central beam frame 18, the rear beam frame 17, and the rear support frame 22, and front and rear support plates 29, 29 that support the engine 30 are provided between the front and rear of the central beam frame 18 and the rear beam frame 17, and between the left and right rear connecting frames 20, 20.

[0030] The front and rear support plates 29, 29 are each provided with receiving plates 29a... that support the engine 30 on both the left and right sides of the central connecting frame 28.

[0031] Furthermore, auxiliary frames 31, 31 are provided on both the left and right sides of the front and rear support plates 29, 29, passing below the rear beam frame 17 and projecting rearward. The rear ends of these auxiliary frames 31, 31 are connected by a rear auxiliary frame 32 in the left-right direction. The rear ends of these auxiliary frames 31, 31 are connected to the left and right rear wheel transmission cases 11a, 11a.

[0032] The main frame 15 is constructed as described above. The front-to-back width of the main frame 15, from the front beam frame 16 to the rear beam frame 17, and the left-to-right width of the left and right front connecting frames 19, 19 and rear connecting frames 20, 20 are covered by floor steps 33 on which workers stand. The floor steps 33 may be integrally formed to improve strength or reduce the number of parts, or they may be constructed to be separable into front and rear, left and right sections, to facilitate attachment and detachment.

[0033] As shown in Figure 3 above, the areas around the left and right ends of the central beam frame 18 and the rear beam frame 17, and the left and right extension frames 27, 27 are not covered by the floor step 33 and are exposed. In this case, the floor step 33 could be enlarged to cover the entire main frame 15, but in order to share the floor step 33 between machines of different sizes and planting row counts, the left and right extension steps 34, 34 are arranged on the left and right sides of the floor step 33, respectively.

[0034] With the above configuration, the main frame 15 is constructed by connecting multiple frame components, thus improving its strength compared to conventional designs.

[0035] Furthermore, by positioning the central connecting frame 28 below the front and rear support plates 29, 29 on which the engine 30 is mounted, and by connecting the front and rear support plates 29, 29 to the left and right rear auxiliary frames 32, 32, the heavy engine 30 can be firmly held in place.

[0036] As shown in Figures 1 and 2, the front of the vehicle body 2 is provided with a bonnet 39 on top, which has a steering handle 35 for steering the machine, a gear shift lever 36 for operating the continuously variable transmission 14 and the work device 4, a sub-gear shift lever 37 for operating a sub-gear shifting device (not shown) for switching the drive transmission of the vehicle body 2, and a control panel 38 for operating various parts of the machine. The front of the bonnet 39 is provided with an openable and closable front cover 40, and inside the front cover 40 are a fuel tank, a battery, and an interlocking mechanism (not shown) that rotates the left and right front wheels 10, 10 and the lower parts of the left and right front wheel transmission cases 10a, 10a for steering the steering handle 35.

[0037] Furthermore, a center mascot 70 is provided in front of the front cover 40, which displays various information such as the working status of the work device 4, the decrease in work materials consumed during work, and the operation or non-operation of the automatic steering device 205 (described later) by lighting up LEDs or the like. The center mascot 70 consists of a work display unit 71 located on the lower and rear side of the machine in a side view, and an automatic straight-ahead display unit 72 located on the upper and front side of the machine.

[0038] Furthermore, an engine cover 30a is provided behind the bonnet 39 and above the engine 30, covering the top and sides of the engine 30, and a work seat 41 on top of the engine cover 30a is provided for the operator to sit on.

[0039] Furthermore, the fertilizer application device 5 is mounted behind the work seat 41, specifically at the rear end of the main frame 15. The driving force of the fertilizer application device 5 is transmitted by a fertilizer transmission mechanism 5a, which is positioned from one side of the left and right rear wheel transmission cases 11a toward the fertilizer application device 5.

[0040] At the front of the transmission case 13 is a front transmission shaft (not shown) that transmits power to the left and right front wheel transmission cases 10a, 10a, and at the rear of the transmission case 13 are left and right drive shafts 42, 42 that transmit power to the left and right rear wheel transmission cases 11a, 11a. Upstream of the left and right drive shafts 42, 42 in the transmission direction are side clutch mechanisms 43, 43 that engage and disengage power to the left and right drive shafts 42, 42. When the steering wheel 35 is turned to rotate the vehicle body 2, the side clutch mechanism 43 located on the inside of the turn is disengaged, stopping power transmission to the rear wheel 11 on the inside of the turn.

[0041] As shown in Figure 3, left and right clutch engagement / disengagement shafts 44, 44 are provided vertically near the left and right center of the rear side of the transmission case 13, and clutch engagement / disengagement arms 45, 45 facing outwards from the aircraft are provided above the left and right clutch engagement / disengagement shafts 44, 44. Side clutch pedals 43a, 43a for engaging and disengaging the left and right side clutch mechanisms 43, 43 are provided on one side of the front lower part of the cockpit seat 41.

[0042] Furthermore, as shown in Figures 1 and 2, below the working device 4, there is a center float 62C and left and right side floats 62L and 62R that make contact with and slide on the field surface. In addition, a leveling rotor 63 for leveling uneven surfaces in the field is provided in front of the machine body, beyond the center float 62C and the left and right side floats 62L and 62R. The driving force to the leveling rotor 63 is transmitted by a leveling transmission shaft 65 provided in one of the left or right rear wheel transmission cases 11a. A leveling clutch 66 for switching the transmission to the leveling rotor 63 on and off is also provided in one of the left or right rear wheel transmission cases 11a.

[0043] The center float 62C is equipped with a rotating potentiometer 64 that detects the rotation angle of the center float 62C. When the rotation angle of the rotating potentiometer 64 changes by more than a predetermined angle, the control device 100 determines that the field depth has changed, and extends or retracts the lifting cylinder 25 to rotate the lifting link mechanism 3 up and down, thereby adjusting the vertical height of the work device 4, i.e., the working position, to correspond to the field depth.

[0044] When using the aforementioned work device 4 in a field to plant seedlings, sow seeds, or perform tasks such as fertilizing or weeding after seedling growth, it is common practice to drive the vehicle body 2 in a straight line from one side of the field to the other. However, if the wheels of the vehicle body 2 deviate from the straight-line direction due to the unevenness of the field's plow pan or the viscosity of the topsoil, the vehicle body 2 may gradually move in the direction of deviation. Furthermore, depending on the operator's driving skill, it may not be possible to keep the vehicle body 2 aligned with the straight-line direction, causing it to move in a direction deviating from the straight line.

[0045] As a result, the work trajectory for planting seedlings, sowing seeds, weeding, and fertilizing becomes diagonal, leaving empty spaces where planting or sowing would normally be possible. This necessitates manual planting or sowing by the worker afterward, creating extra labor for the worker. Furthermore, the spacing between planting rows and sowing rows becomes narrower than the spacing between rows of the work device 4, leading to poor ventilation and potential pest and disease outbreaks. Alternatively, during post-planting or sowing operations such as weeding or fertilizing, seedlings may be crushed, leading to reduced yields. Conversely, maneuvering the device to avoid crushing seedlings can reduce work efficiency.

[0046] To solve these problems, one possible solution is to install an automatic straight-line driving system that automatically steers the vehicle body 2 and maintains a straight-line driving posture without human intervention.

[0047] First, as shown in Figures 1 and 2, an antenna frame 201 for mounting a GPS (GNSS) antenna 200 is provided on the vehicle body 2. The antenna frame 201 consists of a front frame 201a, which is gantry-shaped in a front view, with its left and right bases attached to left and right antenna stays 202, 202 provided on the front side of the main frame 15, and a rear frame 201b that extends from the left and right center of the front frame 201a toward the rear of the vehicle body 2 toward the left and right center of the rear. The bonnet 32 ​​and the cockpit 41 are located behind the space of the gantry-shaped front frame 201a.

[0048] Furthermore, the vertical height of the antenna frame 201 is made the highest in the entire aircraft. In order to prevent workers from hitting their heads while standing on the floor step 33, and to improve reception accuracy, the upper end of the antenna frame 201 is positioned approximately 2.5 to 3.5 meters above the ground.

[0049] This makes it easier for workers to move on the floor steps 33, improving work efficiency, and also allows the GPS antenna 200 to be positioned higher above the ground, thereby improving reception accuracy.

[0050] The GPS antenna 200 is mounted near the connection point between the front frame 201a and the rear frame 201b. The connection point between the front frame 201a and the rear frame 201b is located near the front-to-rear distance between the bonnet 32 ​​and the driver's seat 41, and is near the center of the vehicle body 2 in the front-to-rear direction.

[0051] As a result of the above, the mounting position of the GPS antenna 200 is near the center of the aircraft in both the front-to-back and left-to-right directions, so the acquired coordinates of the aircraft are less likely to deviate from the actual position of the aircraft. This allows for more accurate setting of the straight-line driving position by the automatic straight-line driving system, improving work accuracy.

[0052] Furthermore, because the cockpit 41 is located behind the space in the front frame 201a, the antenna frame 201 does not obstruct the operator's view, improving visibility and allowing for more accurate positioning before straight-line driving. Additionally, the operator can spot the field conditions and obstacles in front of the machine earlier, enabling safer manual operation by the operator while minimizing deviations from the working position.

[0053] Furthermore, the GPS antenna 200 should be one of the following methods, such as standalone positioning, DGPS (Digital GPS) (relative positioning), or RTK (Real-Time Kinematics), that is suitable for the area where the work is being performed.

[0054] However, if the ground clearance of the GPS antenna 200 fluctuates due to the aircraft's tilt or vibration, a coordinate position different from the actual aircraft position will be measured, resulting in a decrease in reception accuracy and causing the aircraft to travel in a direction deviating from a straight line.

[0055] To prevent this, as shown in Figure 6, an IMU (Inertial Measurement Unit) 203 is provided in addition to the GPS antenna 200. The IMU 203 corrects the position coordinates acquired by the GPS antenna 200 to the control device 100 based on the difference between the height from the ground to the GPS antenna 200 when the vehicle body 2 is in an inclined position and the height from the ground to the GPS antenna 200 when it is not inclined.

[0056] The height from the ground surface to the GPS antenna 200 is determined by measuring the tilt and other behaviors of the vehicle body 2 using the three-axis acceleration sensor and angular velocity sensor built into the IMU 203.

[0057] In addition, a compass sensor 204 is provided to allow the control device 100 to more reliably determine whether the aircraft's direction of travel by the automatic straight-line system is correct.

[0058] The position coordinate correction at this time is as shown in S1 to S5 of Figure 7.

[0059] This allows the aircraft's trajectory to be determined by the measured direction, further improving the accuracy of straight-line flight.

[0060] The position information acquired by the GPS antenna 200 is corrected by the control device 100 based on the information detected by the IMU 203 and the direction sensor 204. The control device 100 then compares the current position information with previously acquired position information, and if the difference in position information exceeds an acceptable range, it steers the left and right front wheels 10, 10 in the left and right directions to return the aircraft to a straight-ahead driving position.

[0061] To automate the steering of the left and right front wheels 10, 10, or pivot turning of crawlers, etc., an automatic steering device 205 is provided that rotates the handle 35 with a steering actuator 206. As shown in S6 to S9 of Figure 8, the automatic steering device 205 adjusts the amount of operation of the steering actuator 206 based on the difference between the X coordinate of the current position information calculated by the control device 100 and the X coordinate of the previously acquired reference position information. This causes the handle 35 to be turned left and right to move the machine toward the straight-ahead driving position, and when the machine reaches the straight-ahead driving position, the steering actuator 206 is stopped, and the automatic steering of the handle 35 is stopped.

[0062] The steering actuator 206 consists of an electric or hydraulic motor, or a cylinder.

[0063] With the above configuration, the steering wheel 35 is automatically steered according to the difference in the X coordinate of the calculated position information, and the machine can be automatically adjusted to a straight-line driving position. This prevents the working position of the work device 4 from shifting left or right, making it less likely that there will be areas in the field where work has not been performed. As a result, there is no need to perform work manually in areas where work was not performed, and the workload of the operator is reduced.

[0064] Furthermore, since the working positions of the previous work row and the current work row do not overlap, the consumption of excess materials such as seedlings, seeds, and fertilizers is prevented, thereby reducing working costs and preventing poor growth caused by an oversupply of materials.

[0065] Furthermore, tractors equipped with tillers, seedling transplanters, and seeders travel to the edge of the field for each work row, turn approximately 180 degrees, and move to the next work row. If the automatic straight-line system is activated during a turn, it may determine that the machine is deviating from its intended straight-line position and activate the steering actuator 206, potentially disrupting the turning trajectory. Therefore, the automatic straight-line system must be configured to be turned off when the machine is turning. It is also conceivable to configure the system so that it turns off when the steering wheel 35 is turned. However, if the machine's direction of travel deviates significantly due to field conditions, or if the operator turns the steering wheel 35 to avoid an obstacle, the automatic straight-line system will turn off. This would require the operator to turn the automatic steering system back on mid-way, increasing the operator's workload. Moreover, the operator might not notice that the automatic straight-line system has turned off, causing the machine to travel in a misaligned position and reducing work accuracy.

[0066] Furthermore, it is conceivable that the automatic straight-line system can be activated by returning the steering wheel 35 from a turning position to a straight-line position. However, when returning from a turning position to a straight-line position, fine steering adjustments of the steering wheel 35 are necessary to align the machine with the straight-line position for the next work run. If the automatic steering system is activated during this operation, the control device 100 will determine that the machine has deviated from the straight-line driving position, causing the steering actuator 206 to activate and preventing the machine from being positioned in the straight-line driving position it should have been.

[0067] An automatic straight-line system that prevents this problem from occurring, ensures the aircraft travels in the correct direction in a straight line, and operates within the appropriate section will be explained using Figures 6 and 8 to 11.

[0068] The Y-coordinate represents the position of the vehicle body 2 in the forward and backward direction, while the X-coordinate represents the position of the vehicle body 2 in the direction perpendicular to the forward and backward direction, i.e., the left and right direction.

[0069] First, the vehicle body 2 is equipped with an automatic straight-line setting member 207 that acquires the coordinates of one side of the field, which is the starting point of automatic straight-line movement, and the other side of the field, which is the ending point of automatic straight-line movement, and also turns the automatic straight-line system on and off. The automatic straight-line setting member 207 shall be equipped with at least one member that can be operated in at least two directions, such as vertically, horizontally, or in a pushed-in state and a returned state, or it shall be equipped with two or more operating members.

[0070] In this application, the automatic straight-line setting member 207 is equipped with a finger-up lever that can be operated in the vertical direction, as shown in Figure 4, but a toggle switch, push switch, joystick, etc. may also be used.

[0071] This reduces the number of parts, and improves operability because the operation to acquire the reference positions (first reference position A, second reference position B) and the operation to switch the automatic steering device 205 on and off can be done by operating the automatic straight-ahead setting member 207 with the same hand on the same side.

[0072] As shown in Figure 4, when the automatic straight-line setting member 207 is operated in the first direction W1, which in this application is directed upwards, the GPS antenna 200 acquires data at the operated position, and the control device 100 calculates the position coordinates using the detection results of the IMU 203 and the direction sensor 204 and records them. Note that operating the automatic straight-line setting member 207 in the first direction W1 corresponds to operating the reference position acquisition member.

[0073] When the automatic straight-line setting member 207 is operated, if no other position coordinates are recorded, the calculated position coordinates are recorded as the first reference point A. If the first reference point A is already recorded, the calculated position coordinates are recorded as the second reference point B. When the automatic straight-line setting member 207 is operated while both the first reference point A and the second reference point B are already recorded, no position coordinates are recorded.

[0074] Furthermore, if automatic straight-line movement becomes inaccurate during work in the field, it is necessary to reacquire the first reference point A and the second reference point B. In such cases, as shown in Figure 10, it is advisable to set the automatic straight-line setting member 207 to erase the recorded first reference point A and second reference point B when operated in the first direction W1 for a predetermined time (e.g., 2-3 seconds). Alternatively, a button for erasing the records (not shown) may be provided, which, when operated, deletes the first reference point A and the second reference point B.

[0075] The first reference point A and the second reference point B, which serve as the reference positions for straight-line driving of the automatic straight-line driving system, exhibit smaller X-coordinate deviations the closer they are to each other. However, if the distance between the two points is short, straight-line driving is possible even without using the automatic straight-line driving function. Furthermore, when the distance between the two points is short, it is conceivable that an operator might unintentionally touch the automatic straight-line driving setting member 207, thereby acquiring the second reference point B.

[0076] To prevent this problem from occurring, when the automatic straight-line setting member 207 is operated to acquire the second reference point B, if the distance from the position where the first reference point A was acquired is less than a predetermined distance, for example, less than 8 to 12 m, the control device 100 will delete the second reference point B and will not record it. Subsequently, when the automatic straight-line setting member 207 is operated again and the distance from the position where the first reference point A was acquired is greater than or equal to the predetermined distance, the control device 100 will record the second reference point.

[0077] As shown in Figure 11, if the steering wheel 35 is operated by a predetermined amount or more within a predetermined time while the first reference point A is acquired, without acquiring the second reference point B, and the vehicle body 2 is turned, the control device 100 deletes the recorded first reference point A. Subsequently, when the automatic straight-ahead setting member 207 is operated in the first direction W1, the control device 100 may record the position coordinates of that location acquired by the GPS antenna 200 as the first reference point A, thereby preventing the line connecting the Y coordinate of the first reference point A and the Y coordinate of the second reference point B from becoming a straight line.

[0078] This allows for the setting of a first reference point A and a second reference point B at predetermined positions at one end and the other end of the field, for example, the position where the vehicle body 2 begins to turn after completing a straight-line run, and the position where the work device 4 is lowered and the vehicle begins to run straight after the turn. By activating the automatic straight-line system at the position where the work device 4 is lowered and the vehicle is running straight, high-precision work becomes possible without the work position shifting laterally relative to the direction of travel.

[0079] Furthermore, since it prevents the second reference point B from being set in a different position than it should be due to operator error, there is no need to reacquire the first reference point A and the second reference point B in the next work run. This allows for an increase in the number of work runs using automatic straight-line movement, further improving the accuracy of work within the field.

[0080] Furthermore, in the first work row performed after entering the field, it is essential to operate the automatic straight-line setting member 207 to the first direction W1 at a predetermined position to acquire the first reference point A and the second reference point B mentioned above. Therefore, the automatic straight-line function is not used, and the operator operates the handle 35 to make the machine move in a straight line.

[0081] As described above, once the first reference point A and the second reference point B are acquired by operating the automatic straight-line setting member 207, the reference line R connecting the Y coordinates of the first reference point A and the second reference point B becomes a guideline for automatic straight-line driving. The system then determines whether the X coordinate of the vehicle's position during driving matches the X coordinate of the guideline for automatic straight-line driving. If they do not match, the automatic steering device 205 automatically steers the steering wheel 35 in the direction that matches, thereby achieving automatic straight-line driving.

[0082] The automatic straight-line driving described above is initiated by operating the automatic straight-line setting member 207 in the second direction W2, which in this application is directed downwards, while the first reference point A and the second reference point B are recorded. When the automatic straight-line setting member 207 is operated in the second direction W2, the control device 100 compares the Y coordinate of the position coordinate acquired by the GPS antenna 200 with the Y coordinate of the reference line R, activates the steering actuator 206 to rotate the steering wheel 35 left and right, and starts control to move the vehicle body 2 to the position where it should drive in a straight line. Note that operating the automatic straight-line setting member 207 in the second direction W2 corresponds to operating the on / off member.

[0083] This automatic steering control terminates when the steering wheel 35 is operated to an angle that turns the vehicle body 2 within a predetermined time, or when the automatic straight-ahead setting member 207 is operated to the second direction W2. The steering angle of the steering wheel 35 is detected by the steering wheel potentiometer 35a.

[0084] Furthermore, the system may be configured such that the automatic straight-line control terminates when the vehicle body 2 reaches a location that coincides with the Y coordinate of either the first reference point A or the second reference point B.

[0085] As described above, the automatic straight-line control is terminated when the steering wheel 35 is turned or when the vehicle reaches the vicinity of the starting point for turning at the edge of the field. Since the position where the vehicle 2 turns is close to the edge of the field, if the operator is performing tasks other than steering while the vehicle is left to the automatic straight-line control, a delay in turning will result in seedlings being planted in an unintended location, and the vehicle 2 will move to the edge of the field, requiring it to reverse to the turning position, leading to a decrease in work efficiency.

[0086] Figure 12 is a schematic diagram showing the first reference position A, the second reference position B, the reference line R, and the target position and the current position of the aircraft.

[0087] To prevent this problem, as shown in Figures 6 and 13, a work detection sensor 209 is provided to detect the on / off operation of the leveling clutch 66 and the on / off operation of the leveling rotor 63. When the work detection sensor 209 detects the on / off operation of the leveling rotor 63, the control device 100 acquires the target position coordinates (end reference position), which are the position coordinates (X and Y coordinates) of the traveling vehicle body 2. The control device 100, or a memory area associated with the control device 100, can simultaneously store at least two sets of these target position coordinates.

[0088] Furthermore, the acquisition of target position coordinates (end reference position) by the work detection sensor 209 may be configured to be performed based on conditions such as the raising or lowering of the work device 4, the turning on or off of the power transmission to the work device 4, or the steering start or end of the turn of the handle 35, instead of the turning on or off of the leveling rotor 63.

[0089] Then, in the work run following the work run in which the position coordinates were acquired, when the automatic steering device 205 is activated to automatically drive the vehicle body 2 in a straight line, the control device 100 sequentially calculates the distance from the Y coordinate of the current position coordinates acquired by the GPS antenna 200 to the Y coordinate of the target position coordinates acquired in the previous work run (the most recent work run). At this time, the control device 100 may be configured to correct the X coordinate of the target position coordinates to the X coordinate of the current position coordinates.

[0090] When the vehicle 2 reaches a notification position where the distance from its current position coordinates to the target position coordinates is a predetermined distance, for example, 8 to 12 m, a notification device 208 is activated to inform the operator that the vehicle 2 is approaching the edge of the field and that it is necessary to operate the automatic straight-line setting member 207 in the second direction W2 to terminate the automatic straight-line control. This notification device may activate a buzzer, a lamp, or display numerical values ​​or characters on the screen.

[0091] Furthermore, to display numerical values ​​or characters on the notification device 208, possible configurations include providing a display panel (not shown) on the vehicle body 2, or transmitting and displaying information on an information terminal (smartphone, tablet, etc.) brought in by the worker.

[0092] Furthermore, in work runs where target position coordinates have not been acquired, the distance between the vehicle 2 and the target position cannot be calculated. Therefore, the operator must visually check the edge of the field and operate the automatic straight-line setting member 207 at a position where automatic straight-line control is deemed unnecessary.

[0093] The distance from the current position coordinate to the target position coordinate may be determined by providing rear wheel rotation sensors 210, 210 that detect the rotation of the left and right drive shafts 42, 42 to the left and right rear wheels 11, 11. The control device 100 calculates the travel distance based on the rotation speed detected by the rear wheel rotation sensors 210, 210 from the position where the leveling rotor 63 is turned on, calculates the distance from this travel distance to the Y coordinate position of the position where the leveling rotor 63 is turned on, and activates the notification device 208 if it is within a predetermined distance.

[0094] However, even if the notification device 208 is activated, the vehicle body 2 cannot be turned to the appropriate position unless the operator notices and terminates the automatic straight-line control. To address this, when the vehicle body 2 travels forward for a predetermined distance (for example, 2 to 5 m) after the notification device 208 is activated without the automatic straight-line setting member 207 being operated in the second direction W2, the control device 100 rotates the trunnion shaft 14a of the continuously variable transmission 14 to decelerate the vehicle body 2.

[0095] Alternatively, if, instead of distance, the vehicle body 2 travels forward for a predetermined time (for example, 2 to 5 seconds) after the notification device 208 is activated without the automatic straight-ahead setting member 207 being operated in the second direction W2, the control device 100 reduces the output of the continuously variable transmission 14 and decelerates the vehicle body 2.

[0096] The deceleration of the vehicle body 2 described above is performed by operating an HST servo motor 211 that rotates the trunnion shaft 14a of the continuously variable transmission 14 via a trunnion arm (not shown), thereby rotating the trunnion shaft 14a toward the deceleration side.

[0097] As a result, the vehicle's speed decreases as it approaches the edge of the field, allowing the operator to recognize that the turning point at the edge of the field is approaching, and enabling the vehicle to turn along an appropriate trajectory. Therefore, the work device 4 is prevented from performing repeated ground work on all four sides of the outer perimeter of the field, the so-called headland, and thus avoids the consumption of excess work materials (seedlings, fertilizers, pesticides, etc.).

[0098] Furthermore, since the position where the leveling rotor 63 is turned on after turning and the leveling work begins can be aligned with the position where the leveling work was completed before turning, it is possible to prevent areas where leveling work is not performed by the leveling rotor 63 and areas where ground work is not performed by the work device 4. As a result, problems such as uneven planting depth of seedlings, differences in fertilizer penetration, and erratic movement in areas where leveling work was not performed are prevented, and the operator does not need to perform manual work in areas where ground work was not performed, thus reducing the operator's workload.

[0099] The automatic deceleration described above is configured to gradually reduce the travel speed over time, and by using a control configuration that slows down the vehicle gradually, it is possible to prevent a decrease in the accuracy of the ground work performed by the work device 4 and the leveling accuracy of the leveling rotor 63, as well as to prevent the worker from being shaken around.

[0100] Alternatively, if the control configuration is set to perform abrupt deceleration once or multiple times at predetermined intervals after the automatic deceleration starts, the shaking of the vehicle body 2 will make it easier for the operator to notice the approaching edge of the field.

[0101] Furthermore, if the automatic straight-line control is canceled by operating the automatic straight-line setting member 207 within a predetermined time (second predetermined time) during which automatic deceleration control is performed, the control device 100 may be configured to maintain the travel speed at that time. As a result, since the work travel does not stop, it is possible to quickly transition to turning travel at the edge of the field, and a decrease in work efficiency is prevented.

[0102] Alternatively, the control device 100 may be configured to activate the HST servo motor 211 of the continuously variable transmission 14 to rotate the trunnion shaft 14a in the speed-increasing direction in order to change the speed to a preset travel speed or the travel speed at the time automatic deceleration is initiated.

[0103] Since the travel speed is automatically increased, the operator no longer needs to operate the gear shift lever 36 to increase the travel speed, thus improving operability.

[0104] In addition to the operation of the notification device 208, the automatic deceleration control of the vehicle body 2 described above is expected to allow the vehicle body 2 to recognize the turning position near the edge of the field, specifically near the edge of the field. However, it is conceivable that the worker may not notice the automatic deceleration of the vehicle speed if they are engrossed in another task or if they faint.

[0105] Therefore, the automatic deceleration control of the vehicle body 2 is performed until the continuously variable transmission 14 reaches a neutral state where neither the forward nor reverse travel speed increases or decreases. At this time, the engine 30 is not stopped. This allows the vehicle body 2 to stop in place, preventing it from moving forward until it contacts the edge of the field, the so-called ridge, thus reducing the risk of damage to the machine and minimizing the distance the machine needs to move in reverse to resume work.

[0106] When the vehicle body 2 automatically stops moving due to approaching the edge of the field, returning the gear shift lever 36, which controls the vehicle body 2's speed and forward / reverse movement, to the neutral position causes the control device 100 to accept speed adjustments from the continuously variable transmission 14. Then, when the gear shift lever 36 is moved forward, the vehicle body 2 resumes moving. Naturally, when the auxiliary gear shift lever 37 is moved to the neutral position and no driving force is transmitted to the drive system, the vehicle will not start moving until the auxiliary gear shift lever 37 is moved to a position where the drive force is transmitted.

[0107] The first reference point A and the second reference point B, and the reference line R connecting the first reference point A and the second reference point B, which serve as the basis for the automatic straight-line control described above, are necessary when performing straight-line work from one end of the field to the other, and when performing straight-line work from the other end of the field to one end.

[0108] However, although the work travel along the four sides of the field, the so-called headlands, is in a straight line, there is one side where the direction of travel differs from the straight-line work travel described above, and automatic straight-line control cannot be performed on that side even if the aforementioned reference line R is used.

[0109] Furthermore, when moving the machine to the back of a transport truck or storing it in a barn outside the field, if the automatic straight-line setting member 207 is mistakenly operated to the second direction W2, thereby activating the automatic steering device 205, the X-coordinate of the reference line (R) and the X-coordinate of the machine will not match when the machine is moved. This may cause the machine to deviate from its straight-line driving position, and the automatic steering device 205 may automatically steer the steering wheel 35. As a result, the machine's path will deviate from its intended path, leading to extra work during loading and storage.

[0110] To prevent this, it is necessary to erase the first reference point A, the second reference point B, and the reference line R before the machine leaves the field. As shown in Figures 6 and 14, when the vehicle 2 travels along three sides of the field, including at least one side perpendicular to the direction of travel for straight-line work, the control device 100 determines that headland work has been performed and deletes the first reference point A, the second reference point B, and the reference line R.

[0111] The direction of travel of the vehicle 2 on the headland is determined by the continuous change in the X-axis or Y-axis coordinates of the vehicle 2's position coordinates acquired by the GPS antenna 200.

[0112] This allows the first reference point A, the second reference point B, and the reference line R to be deleted while the machine is moving within the field. As a result, even if the automatic straight-line setting member 207 is operated after leaving the field, automatic straight-line movement will not occur, preventing the machine from traveling in a direction deviating from the intended direction of travel. This prevents a decrease in work efficiency and improves work safety.

[0113] Furthermore, when the machine is moved to a different field, the first reference point A, the second reference point B, and the reference line R are not recorded. This prevents automatic straight-line control from being performed based on a reference line R that is unsuitable for the field being worked on, thus improving the accuracy of automatic straight-line control.

[0114] Furthermore, when moving outside the field, the auxiliary transmission lever 37 is operated to the driving position in order to move it to a transport truck or barn in a short time. An auxiliary transmission position detection switch 37a is provided to detect when the auxiliary transmission lever 37 is operated to the driving position, and when the auxiliary transmission position detection switch 37a detects that the auxiliary transmission lever 37 has been operated to the driving position, the first reference point A, the second reference point B, and the reference line R may be deleted.

[0115] By deleting the first reference point A, the second reference point B, and the reference line R based on the operation of the sub-transmission lever 37 to a driving position not used in the field, if the first reference point A, the second reference point B, and the reference line R have not been deleted when driving on a headland, they can be reliably deleted. This prevents automatic straight-line control from being performed when the vehicle body 2 moves or when working in another field, thus preventing a decrease in work accuracy.

[0116] Furthermore, by preventing accidental deletion of the first reference point A, the second reference point B, and the reference line R in the field due to incorrect operation of the sub-transmission lever 37, the automatic straight-line function is prevented from being unavailable in work runs that reacquire the first reference point A and the second reference point B, thereby improving work accuracy.

[0117] Alternatively, the control device 100 may be configured to delete the first reference point A, the second reference point B, and the reference line R when the vehicle body 2 is tilted forward or backward and left or right by using the IMU 203 and the tilt sensor 212 which detects the tilt of the vehicle body 2 in the front-rear and left-right directions.

[0118] When leaving the field, the vehicle body 2 passing through the field entrance / exit assumes a forward-leaning tilt at an angle that is almost impossible to achieve during operation. Therefore, when this tilt angle is detected, it can be determined that the vehicle is leaving the field.

[0119] This ensures that the first reference point A, the second reference point B, and the reference line R are reliably deleted when the vehicle is traveling along a headland. As a result, automatic straight-line control is not performed when the vehicle body 2 moves or when working in another field, thus preventing a decrease in work accuracy.

[0120] Furthermore, depending on the field and the nature of the work, it may be necessary to reverse the vehicle body 2 to exit the entrance. Therefore, the control configuration may be such that the first reference point A, the second reference point B, and the reference line R are deleted not only based on the forward upward tilt angle but also on the rear upward tilt angle.

[0121] Even when the vehicle body 2 is automatically driven in a straight line by the automatic steering device 205, the operator needs to stop the vehicle when it is necessary to replenish the work materials consumed by the work equipment 4, etc., or when any problems occur with the machine or the field. Possible ways to stop the vehicle include operating the gear shift lever 36 to the neutral position to put the continuously variable transmission 14 into neutral, pressing the brake pedal to apply the brakes, or pressing the side clutch pedal 43a to disengage the side clutch 43.

[0122] Even when the vehicle body 2 is stopped from moving by any of the methods described above, the control device 100 is configured not to stop the automatic steering device 205.

[0123] As a result, when the vehicle is released from a stop by moving the gear shift lever 36 forward or releasing the brake pedal or side clutch pedal 43a, it is possible to immediately resume automatic straight-line driving, thus preventing a decrease in work efficiency.

[0124] However, if the steering wheel 35 is manually steered while stopped, or if the automatic steering device 205 is activated and the steering wheel 35 is automatically steered, the direction of travel when automatic straight-line driving resumes may deviate from the direction of travel when stopped, and the direction of travel of the vehicle body 2 may no longer be in a straight line.

[0125] In particular, when the vehicle 2 is stationary, the position coordinates acquired by the GPS antenna 200 are susceptible to influences such as the Earth's rotation and the revolution of GPS satellites, and may acquire position coordinates that differ from the actual location of the vehicle 2, making it easy to mistakenly believe that it is located far from the reference line R.

[0126] To prevent this, a lever potentiometer 36a is provided to detect the operating position of the gear shift lever 36, and a pedal depression detection switch 213 is provided to detect the depression operation of the brake pedal or clutch pedal. If an operation to stop driving is detected during automatic straight-line driving, the control device 100 is configured not to reflect the steering operation of the steering wheel 35, or to disable the steering wheel 35.

[0127] The configuration that does not reflect the steering operation of the steering wheel 35 means that even if the X coordinate of the position coordinate of the vehicle body 2 when stationary deviates from the X coordinate of the reference line R by a predetermined value or more, the steering actuator 206 will not be activated.

[0128] Furthermore, the configuration that prevents the steering wheel 35 from moving means increasing the operating torque of the steering actuator 206 to lock the steering wheel.

[0129] With the above configuration, deviations in the direction of travel after resuming movement can be prevented, allowing work to be performed in a straight line and improving work accuracy.

[0130] The steering wheel 35 is automatically steered by the steering actuator 206 during automatic straight-line driving. However, if the condition of the field in the path is unsuitable for automatic straight-line driving (rough, deep field, etc.), or if there are obstacles, it is necessary to take evasive action by manual operation.

[0131] The steering operation of the steering wheel 35 by the steering actuator 206 is performed by the following configuration: An input gear 352 is provided at the lower part of the steering shaft 351, which rotates in conjunction with the steering operation of the steering wheel 35, and an output gear 353 is provided on the steering actuator 206.

[0132] The input gear 352 and output gear 353 are housed in a steering gear case 354 located below the steering wheel 35 and steering actuator 206. A relay gear 355 is provided between the input gear 352 and output gear 353 to transmit the driving force by changing the transmission ratio.

[0133] The gear ratios of the input gear 352, output gear 353, and intermediate gear 355 are set to ensure that the torque from manual operation is strong even when the steering actuator 206 is operating, in order to prevent interference with the manual operation of the steering wheel 35.

[0134] This prevents an increase in the force required to manually operate the steering wheel 35 even during automatic straight-line driving, improving operability and ensuring safety during work by reliably avoiding fields and obstacles that may affect driving conditions. [Explanation of Symbols]

[0135] 35. Steering wheel (steering component) 100 Control device 200 GPS antenna (location information acquisition device) 205 Automatic steering system (automatic straight-line driving system) 207 Automatic straight-line setting component (operating component)

Claims

1. Steering components for steering the aircraft, A location information acquisition device that acquires the aircraft's position information, The IMU mounted on the aircraft, A control device that calculates the aircraft's position coordinates using the detection results of the IMU as a supplement to the position information acquired by the position information acquisition device, An automatic straight-line driving device that operates the steering member to cause the aircraft to travel in a straight line, First operating device for switching the automatic straight-line device on and off In a work vehicle equipped with, The control device records position coordinates calculated at least based on position information acquired by the position information acquisition device at different points in the field as a first reference position and a second reference position. A work vehicle characterized in that, with the first reference position and the second reference position recorded, when the automatic straight-line driving by the automatic straight-line device is "on", the automatic straight-line driving by the automatic straight-line device is turned "off" when the first operating tool is operated.

2. The work vehicle according to claim 1, characterized in that when the control device records the first reference position and the second reference position, it calculates the position coordinates using the detection result of the IMU in addition to the position information acquired by the position information acquisition device.

3. The work vehicle further comprises an orientation sensor for detecting the orientation of the machine, and the control device calculates the position coordinates using the position information acquired by the position information acquisition device, the detection result of the IMU, and the detection result of the orientation sensor when recording the first reference position and the second reference position, as described in claim 1 or 2.

4. The work vehicle according to claim 3, characterized in that the control device controls the movement of the machine using the position information acquired by the position information acquisition device, the detection result of the IMU, and the detection result of the direction sensor while the machine is moving in a straight line by the automatic straight-line device.

5. The aforementioned work vehicle is It further includes a second operating device for acquiring a reference position, The second operating device is a push-button switch, The control device is If the push button switch is operated for less than a predetermined time The position coordinates are recorded as the reference position, If the push button switch is operated continuously for a predetermined period of time or longer The characteristic feature is the deletion of the recorded reference position. A work vehicle according to any one of claims 1 to 4.

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