JP7593387B2 - Work vehicles - Google Patents

Description

The present invention relates to a work vehicle that travels in a field and performs ground work using a work implement that travels on the traveling vehicle body.

Some conventional work vehicles are equipped with an automatic steering device that acquires position information for the work start position and work end position when the work equipment 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 drives the vehicle in a straight line. (Patent Document 1)

JP 2016-21890 A

The work vehicle described in Patent Document 1 has the advantage of being easy to operate because it can obtain the positions where the work equipment is turned on and off as the work start position and work end position, eliminating the need to perform operations to obtain the work start position and work end position.

However, if the work equipment is turned on or off by mistake, the work start position or work end position may be acquired at a position different from the position where it should be acquired. When this happens, it is necessary to re-acquire the reference data under different work conditions, during which time the automatic steering device cannot be used, and there is a problem that work driving cannot be performed with high accuracy.

The present invention aims to provide a work vehicle that can solve the above problems and prevent the reference position for straight-ahead driving from being acquired erroneously.

The invention described in claim 1 is a work vehicle including a steering member (35) for steering the vehicle body, a position information acquisition device (200) for acquiring the position coordinates of the vehicle body, an automatic straight-line driving device (205) for operating the steering member (35) to drive the vehicle in a straight line, and a control device (100) for controlling each part of the vehicle body,
A first operating tool is provided for acquiring a reference position that is a reference for the straight-line running of the machine body, and a second operating tool is provided for turning on and off the automatic straight-line running device (205),
The reference position includes at least two positions: a first reference position (A) acquired by the first operating tool at one point in the field, and a second reference position (B) acquired by the first operating tool at another point in the field;
When the second reference position (B) is acquired by the first operating tool, if the distance from the position where the first reference position (A) is acquired is less than a predetermined distance, the second reference position (B) cannot be acquired.
The work vehicle is characterized in that when the second operating device is operated with the first reference position (A) and the second reference position (B) acquired, automatic straight-line driving by the automatic straight-line driving device (205) is turned "on," and when the second operating device is operated while automatic straight-line driving is "on," the automatic straight-line driving device (205) is turned "off."

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According to the invention of claim 1, the machine body can be automatically driven in a straight line based on the acquired reference position, so that the travel trajectory is aligned in a straight line, improving the work accuracy.

In addition, since there is no need to operate the steering member (35) to maintain straight driving, the labor of the operator is reduced. Also, since the acquisition of the reference position and the turning on and off of the automatic straight driving device (205) can be performed with separate operating tools, erroneous operation can be prevented. In addition, for example, erroneous operation in which the operator unintentionally acquires position information can be prevented.

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Side view of seedling transplanter Top view of the seedling transplanter Plan view of main parts of the vehicle body Rear view of the main part of the control unit, including the handle (a) is a rear view of a main part showing the configuration of an automatic steering device of a steering wheel, (b) is a side view of a main part showing the configuration of the automatic steering device of a steering wheel Block diagram showing components related to various controls A flowchart showing a control for correcting acquired position coordinates according to the inclination of the aircraft, etc. Flowchart showing automatic straight-line control by the automatic steering device A flowchart showing how to obtain the first and second reference positions by operating the automatic straight-line driving setting member and how to turn the automatic straight-line driving control on and off. A flowchart showing an erasing operation of the first reference position and the second reference position. 11 is a flowchart showing a control for erasing the first reference position by a steering wheel operation after the first reference position is acquired. A schematic diagram of an operation showing a first reference position, a second reference position, a reference line, and a target position. A flowchart showing the operation of the warning device and the automatic deceleration control when the automatic steering device is not stopped after the warning device is activated. A flowchart showing a control for erasing the first reference position, the second reference position, and the reference line by traveling on the headland of a farm field.

The embodiment of the present invention will be described with reference to the drawings.

In this case, in the plan view, the left side of the aircraft's direction of travel is referred to as one side of the aircraft's left or right, and the right side of the aircraft's direction of travel is referred to as the other side of the aircraft's left or right. Details of each part are described below.

The riding rice transplanter shown in FIG. 2 as an example of the working machine of the present invention has an eight-row planting configuration, but this configuration may be used for rice transplanters with a different number of planting rows. As shown in FIG. 1 and FIG. 2, the present rice transplanter is provided with a seedling planting section that takes seedlings from a seedling tank 53 and plants them in the field with multiple seedling planting devices 55..., a sowing device that supplies seeds, or a rotary that tills the field, which can be raised and lowered via a lifting link device 3 at the rear of the traveling body 2, and the main body of the fertilizer applicator 5 is located at the upper rear of the traveling body 2.

First, we will explain the main frame 15 that constitutes the running vehicle body 2.

As shown in FIG. 3, the main frame 15 has a front beam frame 16 at the front of the aircraft, a rear beam frame 17 at the rear of the aircraft, and a central beam frame 18 between the front and rear beam frames 16 and 17. The front beam frame 16 and 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 rear beam frame 17 are connected by a pair of left and right rear connecting frames 20, 20.

The longitudinal direction of the front beam frame 16, the central beam frame 18, and the rear beam frame 17 is the left-right direction, while the longitudinal direction of the front connecting frame 19 and the rear connecting frame 20 is the front-to-rear direction.

The left and right front connecting frames 19, 19 and the left and right rear connecting frames 20, 20 are spaced approximately the same apart. The left and right length of the center beam frame 18 and the rear beam frame 17 is longer than the left and right length 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 center 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 square timber.

The space formed by the front beam frame 16, center beam frame 18, and 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, rear wheels 11, 11, working device 4, etc., and a hydraulic continuously variable transmission (HST) 14 that outputs driving force supplied from the engine 30 to the transmission case 13.

Left and right lifting frames 21, 21 are provided at the rear of the rear beam frame 18, protruding rearward at a distance narrower than the left and right distance between the left and right rear connecting frames 20, 20, and a rear support frame 22 is attached to the lower parts 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 traveling 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.

The lifting link mechanism 3 is configured by providing a pair of left and right lower link arms 24, 24 below and between the left and right link frames 23, 23, 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 on the opposite side to the traveling vehicle body 2 are attached to the front side of the machine body of the working device 4.

Furthermore, front transmission cases 10a, 10a that transmit power to the left and right front wheels 10, 10 of the traveling body 2 are provided in front of both left and right ends of the center beam frame 18 and on the left and right outsides of the left and right front connecting frames 19, 19, respectively, and the left and right ends of the center 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 have their longitudinal direction in the front-to-rear direction.

In addition, a central connecting frame 28 in the front-rear direction is provided at the bottom of the central beam frame 18, rear beam frame 17, and rear support frame 22, and front and rear support plates 29, 29 are provided between the front and rear of the central beam frame 18 and rear beam frame 17 and between the left and right rear connecting frames 20, 20 to support the engine 30.

The front and rear support plates 29, 29 each have a support plate 29a that supports the engine 30 on both the left and right sides of the central connecting frame 28.

Left and right auxiliary frames 31, 31 that pass under the rear beam frame 17 and protrude rearward are provided on both the left and right sides of the front and rear support plates 29, 29, and the rear parts of the left and right auxiliary frames 31, 31 are connected to a left and right rear auxiliary frame 32. The rear ends of the left and right auxiliary frames 31, 31 are connected to the left and right rear wheel transmission cases 11a, 11a.

The main frame 15 is constructed as described above. The front-to-rear 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 the rear connecting frames 20, 20 are covered with a floor step 33 on which the worker boards. The floor step 33 is either one-piece formed to improve strength and reduce the number of parts, or one that can be separated into front and rear, left and right sides for easy attachment and detachment.

As shown in Figure 3, the periphery of the left and right side end portions of the center beam frame 18 and 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 may be expanded to cover the entire main frame 15, but in order to share the floor step 33 between machines of different sizes and numbers of planting rows, the left and right extension steps 34, 34 are arranged on the left and right sides of the floor step 33.

With the above configuration, the main frame 15 is made up of multiple connected frame structures, which improves its strength compared to conventional models.

In addition, a central connecting frame 28 is placed under the front and rear support plates 29, 29 on which the engine 30 is mounted, and the front and rear support plates 29, 29 are connected to the left and right rear auxiliary frames 32, 32, so that the engine 30, which is a heavy object, can be firmly supported.

As shown in Figures 1 and 2, a bonnet 39 is provided at the front of the traveling body 2, which has at its top a handlebar 35 for steering the vehicle, a speed change lever 36 for operating the continuously variable transmission 14 and the working device 4, an auxiliary speed change lever 37 for operating an auxiliary speed change switch device (not shown) for switching the traveling transmission of the traveling body 2, and an operation panel 38 for operating each part of the vehicle. An openable front cover 40 is provided in front of the bonnet 39, and inside the front cover 40 are installed a fuel tank, a battery, and an interlocking mechanism (not shown) for rotating the left and right front wheels 10, 10, and the lower sides of the left and right front wheel transmission cases 10a, 10a when the handlebar 35 is steered.

In addition, a center mascot 70 is provided in front of the front cover 40 to display various information such as the working status of the working device 4, the reduction in work materials consumed during work, and the operation/non-operation of the automatic steering device 205 (described later) by lighting up LEDs or the like. The center mascot 70 is composed of a work display unit 71 located on the lower and rear side of the machine body in a side view, and an automatic straight-line display unit 72 located on the upper and front side of the machine body.

An engine cover 30a that covers the top and sides of the engine 30 is provided behind the bonnet 39 and above the engine 30, and a work seat 41 on which an operator sits is provided above the engine cover 30a.

The fertilizer applicator 5 is mounted behind the work seat 41, specifically on the rear end side of the main frame 15. The driving force of the fertilizer applicator 5 is transmitted by a fertilizer transmission mechanism 5a arranged from one of the left and right rear wheel transmission cases 11a toward the fertilizer applicator 5.

A front transmission shaft (not shown) that transmits power to the left and right front wheel transmission cases 10a, 10a is provided at the front of the transmission case 13, and left and right drive shafts 42, 42 that transmit power to the left and right rear wheel transmission cases 11a, 11a are provided at the rear of the transmission case 13. Side clutch mechanisms 43, 43 that turn on and off the power transmission to the left and right drive shafts 42, 42 are arranged upstream of the left and right drive shafts 42, 42 in the transmission direction, and when the handlebars 35 are turned to turn the traveling vehicle body 2, the side clutch mechanism 43 located on the inside of the turn is turned off, stopping the power transmission to the rear wheel 11 on the inside of the turn.

As shown in Figure 3, left and right clutch on/off shafts 44, 44 are provided vertically near the center of the left and right rear of the transmission case 13, and clutch on/off arms 45, 45 facing the outside of the aircraft are provided on the upper parts of the left and right clutch on/off shafts 44, 44. Side clutch pedals 43a, 43a for turning on and off the left and right side clutch mechanisms 43, 43 are provided on the lower front side of the pilot's seat 41 on either the left or right side.

As shown in Figures 1 and 2, a center float 62C and left and right side floats 62L, 62R that slide on the field surface are provided below the working device 4, and a ground leveling rotor 63 that levels the unevenness of the field surface is provided forward of the center float 62C and the left and right side floats 62L, 62R. The driving force to the ground leveling rotor 63 is transmitted by a ground leveling transmission shaft 65 provided in one of the left and right rear wheel transmission cases 11a. In addition, a ground leveling clutch 66 that switches the transmission to the ground leveling rotor 63 on and off is provided in one of the left and right rear wheel transmission cases 11a.

The center float 62C is provided with a rotation potentiometer 64 that detects the rotation angle of the center float 62C. When the rotation angle of the rotation potentiometer 64 changes by a predetermined angle or more, it is determined that the depth of the field has changed, and the control device 100 extends and retracts the lifting cylinder 25 to rotate the lifting link mechanism 3 up and down, and the vertical height of the working device 4, i.e., the working position, corresponds to the depth of the field.

When using the working device 4 in a field to plant seedlings, sow seeds, or perform tasks such as fertilizing or weeding after seedlings have grown, the traveling body 2 is generally driven in a straight line from one side of the field to the other. However, if the unevenness of the tilled bed or the viscosity of the topsoil causes the wheels to point in a direction that deviates from the straight-ahead direction, the traveling body 2 may gradually move in the deviated direction. Also, depending on the operator's driving technique, the traveling body 2 may not be able to align with the straight-ahead direction, causing it to move in a direction that deviates from the straight-ahead direction.

As a result, the trajectory of work such as planting seedlings, sowing, weeding, and fertilizing becomes diagonal, leaving areas where seedlings can be planted or sowed empty, requiring workers to plant or sow the seeds manually later, which creates extra labor for the workers and may result in the spacing between seedling planting rows or sowing rows being narrower than the spacing between rows of the work device 4, resulting in poor ventilation and the occurrence of pests and diseases. Alternatively, when performing work subsequent to planting or sowing, such as weeding or fertilizing, the seedlings may be trampled, resulting in a decrease in yield, or the efficiency of work may be reduced by maneuvering to avoid trampling the seedlings.

To solve these problems, it is possible to equip the vehicle with a so-called automatic straight-line driving system that automatically steers the traveling vehicle body 2 and maintains a straight-line driving posture without the help of an operator.

First, as shown in Figures 1 and 2, an antenna frame 201 for mounting a GPS (GNSS) antenna 200 is provided on the traveling vehicle body 2. The antenna frame 201 is composed of a gate-shaped front frame 201a in a front view, with 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 aircraft and toward the left and right center of the rear side of the traveling vehicle body 2. The bonnet 32 and the pilot's seat 41 are located behind the space of the gate-shaped front frame 201a.

The antenna frame 201 is also made the tallest in both vertical height and height within the aircraft. In order to prevent an operator from hitting his/her head 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 m above the ground.

This allows workers to move easily on the floor step 33, improving work efficiency, and also allows the GPS antenna 200 to be positioned above the ground, improving reception accuracy.

The GPS antenna 200 is attached near the connection between the front frame 201a and the rear frame 201b. The connection between the front frame 201a and the rear frame 201b is located near the front-rear area between the bonnet 32 and the driver's seat 41, and near the center of the traveling vehicle body 2 in the fore-and-aft direction.

As a result of the above, the GPS antenna 200 is attached near the center of the aircraft in the front-to-rear and left-to-right directions, so the aircraft coordinates obtained are less likely to deviate from the actual aircraft position, and the automatic straight-line driving system can properly set the straight-line driving position, improving work accuracy.

In addition, by positioning the pilot's seat 41 behind the space in the front frame 201a, the antenna frame 201 is prevented from blocking the operator's view, improving visibility and allowing for accurate alignment before driving straight ahead. In addition, the operator can quickly find the field conditions and obstacles in front of the vehicle, allowing the operator to switch to manual operation safely and minimizing deviations in the work position.

It is advisable to use the GPS antenna 200 that is suitable for the area where work is being carried out, among the point positioning method, DGPS (distance relative positioning) method, RTK (interferometric positioning) method, etc.

However, if the height above the ground of the GPS antenna 200 fluctuates due to the inclination or vibration of the aircraft, a coordinate position different from the actual aircraft position is measured, reducing reception accuracy and causing the aircraft to travel in a direction that deviates from a straight line.

To prevent this, as shown in FIG. 6, an IMU (inertial measurement unit) 203 is provided in addition to the GPS antenna 200. The IMU 203 causes the control device 100 to correct the position coordinates acquired by the GPS antenna 200 based on the difference between the height from the ground surface to the GPS antenna 200 when the traveling vehicle body 2 is inclined and the height from the ground surface to the GPS antenna 200 when it is not inclined.

The height from the ground to the GPS antenna 200 is calculated by measuring the tilt and other behavior of the traveling vehicle body 2 using a three-axis acceleration sensor and an angular velocity sensor built into the IMU 203.

In addition, a direction sensor 204 is provided to allow the control device 100 to more reliably determine whether the direction in which the aircraft is traveling according to the automatic straight-line driving system is correct.

The correction of the position coordinates at this time is as shown in S1 to S5 of Figure 7.

This allows the aircraft's course to be determined based on the measured direction, further improving the accuracy of straight-line driving.

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 orientation sensor 204. The control device 100 then compares the current position information with the previously acquired position information, and if the difference between the position information exceeds an acceptable range, steers the left and right front wheels 10, 10 in the left and right directions to return the vehicle to a straight-ahead driving position.

To automate the steering of the left and right front wheels 10, 10 or the pivot turning of crawlers, etc., an automatic steering device 205 is provided that rotates the steering wheel 35 with a steering actuator 206. As shown in S6 to S9 of FIG. 8, the automatic steering device 205 changes 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 reference position information previously acquired, thereby turning the steering wheel 35 left or right to move the vehicle toward a straight-ahead driving position, and stopping the steering actuator 206 when the vehicle reaches the straight-ahead driving position, thereby stopping the automatic steering of the steering wheel 35.

The steering actuator 206 is composed of an electric or hydraulic motor or a cylinder.

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 body can be automatically aligned to a straight-ahead driving position, preventing the work 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 done. This eliminates the need to manually work on areas where work has not been done, reducing the labor required by the worker.

In addition, since the work positions of the previous process and the current process can be prevented from overlapping, excessive consumption of work materials such as seedlings, seeds, and fertilizer is prevented, reducing work costs and preventing poor growth due to an oversupply of work materials.

In addition, a tractor equipped with a tiller, a seedling transplanter, or a sowing machine travels to the edge of the field of the work row, turns about 180 degrees, and moves to the next work row. If the automatic straight-line system is activated during a turn, it may determine that the machine is moving away from the position where it should be moving straight, and operate the steering actuator 206, which may disrupt the turning trajectory. Therefore, the automatic straight-line system must be configured to be turned off when the machine is turned. It is possible to configure the automatic straight-line system to be turned off when the handle 35 is turned, but the automatic straight-line system will be turned off when the machine's traveling direction is significantly shifted due to the condition of the field, or when the operator operates the handle 35 to a degree equal to or greater than the turning operation to avoid an obstacle. Therefore, the operator must turn the automatic steering system on again while moving straight, which increases the operator's work, and the machine may not realize that the automatic straight-line system has been turned off, causing the machine to move away from the work position, resulting in a problem of reduced work accuracy.

It is also conceivable to turn on the automatic straight-line driving system by operating the steering wheel 35 to return from turning to straight-line driving, but when returning from turning to straight-line driving, fine steering operation of the steering wheel 35 is required to align the aircraft with the straight-line driving position for the next task. If the automatic steering system is on during this operation, the steering actuator 206 will be activated if the control device 100 determines that the aircraft has deviated from the straight-line driving position, and there is a problem that the aircraft will not be positioned in the position where it should be for straight-line driving.

Using Figures 6 and 8 to 11, we will explain an automatic straight-line system that prevents this problem from occurring, allows the aircraft to travel straight in the appropriate direction, and can operate in the appropriate section.

The position coordinate in the forward/reverse direction of the traveling vehicle body 2 is defined as the Y coordinate, and the position coordinate in the direction perpendicular to the forward/reverse direction of the traveling vehicle body 2, i.e., the left/right direction, is defined as the X coordinate.

First, the traveling vehicle body 2 is provided with an automatic straight-line driving setting member 207 that acquires the coordinates of one side of the field that is the start point of automatic straight-line driving and the other side of the field that is the end point of automatic straight-line driving, and turns the automatic straight-line driving system on and off. The automatic straight-line driving setting member 207 is equipped with at least one member that can be operated in at least two directions, such as up and down, left and right, or a pushed-in state and a returned state, or is equipped with two or more operating members.

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

This reduces the number of parts and improves operability because the operation of obtaining the reference positions (first reference position A, second reference position B) and the operation of turning the automatic steering device 205 on and off can be performed by operating the automatic straight-line setting member 207 with one hand on the same side.

As shown in FIG. 4, when the automatic straight-line setting member 207 is operated in a first direction W1, in this application toward the upper side of the aircraft, the GPS antenna 200 is acquired at the operated position, and the position coordinates calculated by the control device 100 using the detection results of the IMU 203 and the orientation sensor 204 are recorded. Note that the operation of the automatic straight-line setting member 207 in the first direction W1 corresponds to the operation of the reference position acquisition member.

When the automatic straight-line setting member 207 is operated, if no other position coordinates have been recorded, the calculated position coordinates are recorded as the first reference point A, and if the first reference point A has been recorded, the calculated position coordinates are recorded as the second reference point B. If the automatic straight-line setting member 207 is operated when the first reference point A and the second reference point B have been recorded, the position coordinates are not recorded.

When automatic straight-line driving cannot be performed accurately during work in the field, it is necessary to re-acquire the first and second reference points A and B. As shown in FIG. 10, in this case, it is recommended to set the automatic straight-line driving setting member 207 so that the recorded first and second reference points A and B are erased when the member is operated in the first direction W1 for a predetermined period of time (e.g., 2 to 3 seconds). Alternatively, a record erasure button (not shown) may be provided, which will delete the first and second reference points B when operated.

The closer the distance between the first reference point A and the second reference point B, which are the reference positions for straight-line driving by the automatic straight-line driving system, the smaller the deviation in the X coordinate will be. However, if the distance between the two points is short, straight-line driving is generally possible without using automatic straight-line driving. Also, when the distance between the two points becomes short, it is possible that the operator will unintentionally touch the automatic straight-line driving setting member 207 and obtain the second reference point B.

To prevent this problem from occurring, when the automatic straight-line setting member 207 is operated to obtain the second reference point B, if the distance from the position where the first reference point A was obtained 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 not record it. After that, if the automatic straight-line setting member 207 is operated again and the distance from the position where the first reference point A was obtained is equal to or greater than the predetermined distance, the control device 100 will record the second reference point.

As shown in FIG. 11, when the first reference point A is acquired, and the steering wheel 35 is operated by a predetermined amount or more within a predetermined time without acquiring the second reference point B, causing the traveling vehicle body 2 to turn, the control device 100 deletes the recorded first reference point A. After that, when the automatic straight-ahead setting member 207 is operated in the first direction W1, the control device 100 may be configured to record the position coordinates of that location acquired by the GPS antenna 200 as the first reference point A, and to prevent 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.

This allows the first reference point A and the second reference point B to be set at predetermined positions at one end and the other end of the field, for example, the position where the traveling vehicle body 2 finishes traveling in a straight line and starts turning, and the position where the working implement 4 is lowered and starts traveling in a straight line after turning is completed, and the automatic straight-line system is activated at the position where the working implement 4 is lowered and traveling in a straight line, enabling high-precision work without the working position shifting left or right relative to the direction of travel.

In addition, because it is possible to prevent the second reference point B from being different from the position that should actually be set due to an operator error, there is no need to re-acquire the first reference point A and the second reference point B for the next work row, and it is possible to increase the number of work rows that use automatic straight-line driving, further improving the accuracy of work in the field.

In addition, when performing the first work after entering the field, it is necessary to operate the automatic straight-line setting member 207 in a specified position in the first direction W1 to obtain the above-mentioned first reference point A and second reference point B, so automatic straight-line travel is not used, and the operator operates the handle 35 to drive the machine in a straight line.

As described above, when the first reference point A and the second reference point B are obtained 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 line that serves as a guide for automatic straight-line driving, and it is determined whether the X coordinate of the position coordinates of the vehicle while traveling matches the X coordinate of the line that serves as a guide for automatic straight-line driving. If they do not match, the automatic steering device 205 automatically steers the steering wheel 35 in the matching direction, thereby achieving automatic straight-line driving.

The above-mentioned automatic straight-ahead driving is started by operating the automatic straight-ahead setting member 207 in the second direction W2, which in this application is toward the bottom of the vehicle body, while the first reference point A and the second reference point B are recorded. When the automatic straight-ahead setting member 207 is operated in the second direction W2, the control device 100 compares the Y coordinate of the position coordinates acquired by the GPS antenna 200 with the Y coordinate of the reference line R, and starts control to operate the steering actuator 206 to rotate the handlebars 35 left and right, and move the vehicle body 2 to a position where it should travel straight. Note that the operation of the automatic straight-ahead setting member 207 in the second direction W2 corresponds to the operation of the on/off member.

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

In addition, the automatic straight-line control may be configured to end 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.

As described above, the automatic straight-line control ends when the steering wheel 35 is turned or when the vehicle body 2 reaches the start point of the turn at the edge of the field. Because the position at which the vehicle body 2 turns is close to the edge of the field, if the operator leaves the automatic straight-line control to perform tasks other than steering, a delay in turning the vehicle body 2 could result in seedlings being planted in an unplanned position, and the vehicle body 2 could move to the edge of the field, requiring the vehicle to reverse until it is ready to turn, resulting in reduced work efficiency.

Note that FIG. 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 current aircraft position.

To prevent this problem, as shown in Figures 6 and 13, a work detection sensor 209 is provided that detects the on/off of the grading rotor 63 by turning on (operating) and off (stopping) the grading clutch 66. When the work detection sensor 209 detects the on/off of the grading rotor 63, the control device 100 acquires the target position coordinates (end reference position), which are the position coordinates (X coordinate and Y coordinate) of the traveling vehicle body 2. Note that the target position coordinates can be stored simultaneously for at least two locations in the control device 100 or in a memory area associated with the control device 100.

In addition, the acquisition of the target position coordinates (end reference position) by the work detection sensor 209 may be performed based on the conditions of the raising or lowering of the work device 4, the turning on or off of the transmission to the work device 4, the steering of the handle 35 to start turning or the steering of the handle 35 to end turning, etc., instead of the turning on or off of the leveling rotor 63.

Then, in the operation article following the operation article for which the position coordinates were acquired, when the automatic steering device 205 is operated to automatically drive the traveling 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 immediately preceding operation article (the most recent operation article). 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.

When the traveling vehicle body 2 reaches a notification position where the distance from the current position coordinates to the target position coordinates is a predetermined distance, for example 8 to 12 m, the notification device 208 is configured to operate with a buzzer or lamp, or to display numbers or letters on a screen, to notify the operator that the traveling vehicle body 2 is approaching the edge of the field and that the automatic straight-line setting member 207 needs to be operated in the second direction W2 to end the automatic straight-line control.

The numbers and letters can be displayed on the notification device 208 by providing a display panel (not shown) on the traveling vehicle body 2, or by transmitting the information to an information terminal (smartphone, tablet, etc.) carried by the worker for display.

In addition, in a work row where the target position coordinates have not been acquired, the distance between the traveling vehicle body 2 and the target position cannot be calculated, so the worker must visually check the edge of the field and operate the automatic straight-line setting member 207 at a position where the worker determines that automatic straight-line control is not required.

Regarding the distance from the current position coordinates to the target position coordinates, rear wheel rotation sensors 210, 210 are provided to detect the rotation of the left and right drive shafts 42, 42 to the left and right rear wheels 11, 11, and the control device 100 calculates the travel distance based on the number of rotations detected by the rear wheel rotation sensors 210, 210 from the position where the ground leveling rotor 63 is turned on, calculates the distance between the travel distance and the Y coordinate position of the position where the ground leveling rotor 63 is turned on, and activates the alarm device 208 if it is within a predetermined distance.

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

Alternatively, when the vehicle body 2 travels forward without the automatic straight-line setting member 207 being operated in the second direction W2 for a predetermined time (e.g., 2 to 5 seconds) after the alarm device 208 is activated, rather than the distance, the control device 100 reduces the output of the continuously variable transmission 14 to decelerate the vehicle body 2.

The deceleration of the traveling vehicle body 2 is achieved by operating the HST servo motor 211, which rotates the trunnion shaft 14a of the continuously variable transmission 14 via a trunnion arm (not shown), and rotating the trunnion shaft 14a toward the deceleration side.

As a result, the traveling speed of the traveling vehicle body 2 decreases when approaching the edge of the field, allowing the worker to recognize that the turning position of the edge of the field is approaching, and the vehicle can turn along an appropriate trajectory. This prevents the working device 4 from performing redundant ground work on the four sides of the perimeter of the field, the so-called pillow areas, and thus prevents excessive consumption of work materials (seedlings, fertilizer, chemicals, etc.).

In addition, the position where the leveling rotor 63 is turned on and leveling work begins after turning can be aligned with the position where leveling work ended before turning, preventing the occurrence of 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. This prevents problems such as inconsistent planting depth of seedlings, different penetration of fertilizer, and irregular travel in areas where leveling work was not performed, and reduces the labor of the worker as there is no need for the worker to manually work in areas where ground work was not performed.

The above-mentioned automatic deceleration is a gradual decrease in the running speed over time. If the control configuration is such that the speed is gradually decreased, the ground work accuracy of the work device 4 and the ground leveling accuracy of the ground leveling rotor 63 will not decrease, and the worker will not be shaken.

Alternatively, if the control is configured to perform sudden deceleration once or multiple times at predetermined intervals after automatic deceleration begins, the shaking of the traveling vehicle body 2 will make it easier for the operator to notice the approach of the edge of the field.

In addition, if the automatic straight-line control is released by operating the automatic straight-line setting member 207 within a predetermined time (second predetermined time) during which the automatic deceleration control is being performed, the control device 100 may be configured to maintain the travel speed at that time. This allows the work travel to be continued without stopping, and allows for a quick transition to turning travel at the edge of the field, preventing a decrease in work efficiency.

Alternatively, in order to change the travel speed to a preset speed or to the travel speed at the time when automatic deceleration is started, the control device 100 may be configured to operate the HST servo motor 211 of the continuously variable transmission 14 to rotate the trunnion shaft 14a to the speed-up side.

By automatically increasing the travel speed, the operator no longer needs to operate the gear shift lever 36 to increase the travel speed, improving operability.

In addition to the operation of the alarm device 208, the automatic deceleration control of the traveling vehicle body 2 is expected to enable the traveling vehicle body 2 to recognize the edge of the field, specifically the turning position near the edge of the field. However, it is possible that the worker may be engrossed in another task or may faint, and may not notice the automatic deceleration of the traveling speed.

Therefore, the automatic deceleration control of the traveling vehicle body 2 is performed until the continuously variable transmission 14 reaches a neutral state where it does not increase or decrease the traveling speed in either the forward or reverse direction. At this time, the engine 30 is not stopped. This allows the traveling vehicle body 2 to be stopped on the spot, preventing the vehicle from moving forward until it comes into contact with the edge of the field, or the so-called ridge, thereby minimizing damage to the vehicle and the distance it must move backward to return to work.

When the traveling vehicle body 2 automatically stops traveling due to approaching the edge of the field, returning the speed change lever 36, which controls the increase/decrease in traveling speed and forward/reverse movement of the traveling vehicle body 2, to the neutral position causes the control device 100 to be in a state in which the continuously variable transmission 14 can accept operations to increase/decrease the traveling speed. Then, when the speed change lever 36 is operated to the forward side, the traveling vehicle body 2 resumes traveling. Naturally, when the auxiliary speed change lever 37 is operated to the neutral position and the driving force is not transmitted to the traveling system, traveling will not start until the auxiliary speed change lever 37 is operated to a position where traveling transmission is performed.

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 above-mentioned automatic straight-line control, are necessary when driving straight from one end of the field to the other end, and when driving straight from the other end of the field to one end.

However, although the work travel on the four sides of the field, the so-called pillow area, is straight-line work travel, there is one work side that moves in a different direction from the straight-line work travel described above, and automatic straight-line control cannot be performed on that work side even if the reference line R is used.

Furthermore, when the machine is moved to the bed of a transport truck outside the field or stored in a barn, if the automatic straight-line setting member 207 is mistakenly operated in the second direction W2 to put the automatic steering device 205 into an operable state, the X coordinate of the reference line (R) and the X coordinate of the machine will not match when the machine is moved, and it will be determined that the machine has deviated from its straight-line driving position, causing the automatic steering device 205 to automatically steer the steering wheel 35. This will cause the machine to deviate from its intended path, resulting in extra work being required to load and store the machine.

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 traveling vehicle body 2 travels along three of the four sides of the field, including at least one side perpendicular to the direction of travel for straight-ahead work travel, it is determined that headland work has been performed, and the control device 100 erases the first reference point A, the second reference point B, and the reference line R.

The direction of travel of the vehicle body 2 on the headland is determined by continuous changes in the X-axis coordinate or Y-axis coordinate of the position coordinates of the vehicle body 2 acquired by the GPS antenna 200.

As a result, the first reference point A, the second reference point B, and the reference line R can be deleted while the machine is traveling within the field, so that automatic straight-line travel will not be performed even if the automatic straight-line travel setting member 207 is operated after the machine leaves the field, and traveling in a direction that deviates from the planned direction of travel is prevented, preventing a decrease in work efficiency and improving work safety.

In addition, when the machine is moved to another field, the first reference point A, the second reference point B, and the reference line R are not recorded, which prevents automatic straight-line control from being performed based on a reference line R that is not suitable for the field being worked on, thereby improving the accuracy of automatic straight-line driving.

When the machine is moved outside the field, the auxiliary transmission lever 37 is operated to the travel position so that the machine can be quickly moved to a transport truck or to a barn. An auxiliary transmission position detection switch 37a is provided to detect the operation of the auxiliary transmission lever 37 to the travel position, and when the auxiliary transmission position detection switch 37a detects that the auxiliary transmission lever 37 has been operated to the travel position, the first reference point A, the second reference point B, and the reference line R may be deleted.

By removing the first and second reference points A and B, and the reference line R, by operating the sub-gear shift lever 37 to a driving position that is not used in the field, the first and second reference points A and B, and the reference line R can be reliably removed when they are not removed while traveling on the headland, so that automatic straight-line control is not performed when the traveling body 2 moves or when working in another field, and a decrease in work accuracy is prevented.

In addition, it is possible to prevent the first reference point A, the second reference point B, and the reference line R from being mistakenly deleted in the field due to an incorrect operation of the sub-transmission operation lever 37, which prevents the automatic straight-line driving from becoming unavailable in the work section where the first reference point A and the second reference point B are re-acquired, improving work accuracy.

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 traveling vehicle body 2 assumes a forward-backward and left-right inclination posture of a predetermined angle or more (e.g., 10 to 15 degrees) using the IMU 203 or an inclination sensor 212 that detects the inclination of the traveling vehicle body 2 in the forward-backward and left-right directions.

When exiting the field, the vehicle body 2 passes through the entrance/exit of the field and assumes a front-up inclined position at an angle that is almost impossible during work, so when this inclination angle is detected, it can be determined that it is time to exit the field.

This ensures that the first reference point A, the second reference point B, and the reference line R are deleted when they are not deleted while traveling on the headland, so that automatic straight-line control is not performed when the traveling vehicle body 2 moves or when working in another field, preventing a decrease in work accuracy.

Note that, depending on the field and the type of work, it may be necessary to reverse the traveling vehicle body 2 to exit the entrance/exit, so the control configuration may be such that the first reference point A, the second reference point B, and the reference line R are deleted based on not only the front upward tilt angle but also the rear upward tilt angle.

Even when the automatic steering device 205 is causing the traveling vehicle body 2 to travel automatically in a straight line, the operator needs to stop the traveling in cases such as when replenishing the work materials consumed by the working device 4, or when some problem occurs with the machine or the field. Possible methods for this operation to stop traveling include operating the speed change operation lever 36 to the neutral position to put the continuously variable transmission 14 into neutral, stepping on the brake pedal to apply the brakes, or stepping on the side clutch pedal 43a to put the side clutch 43 in the disengaged state.

Even when the traveling vehicle body 2 is stopped by any of the above methods, the control device 100 is configured not to stop the automatic steering device 205.

As a result, when the vehicle is released from the stopped state by operating the gear shift lever 36 forward or by releasing the brake pedal or side clutch pedal 43a, the vehicle can immediately return to automatic straight-ahead driving, preventing a decrease in work efficiency.

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-ahead driving is resumed may deviate from the direction of travel when the vehicle was stopped, and the direction of travel of the traveling vehicle body 2 may no longer be straight.

In particular, when the traveling vehicle body 2 is stopped, the position coordinates acquired by the GPS antenna 200 are easily affected by the rotation of the Earth and the revolution of the GPS satellites, and the acquired position coordinates may differ from the actual position of the traveling vehicle body 2, which may lead to the vehicle body being mistakenly believed to be located away from the reference line R.

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

A configuration that does not reflect the steering operation of the handlebars 35 means that the steering actuator 206 is not operated even if the X coordinate of the position coordinates of the traveling vehicle body 2 when stopped deviates from the X coordinate of the reference line R by a predetermined value or more.

In addition, the configuration that prevents the steering wheel 35 from moving means increasing the operating torque of the steering actuator 206 and locking the steering wheel.

The above configuration prevents deviations in the direction of travel after travel resumes, so work travel is performed in a straight line, improving work accuracy.

The steering wheel 35 is automatically steered by the steering actuator 206 during automatic straight-ahead driving, but if the condition of the field along the route is not suitable for automatic straight-ahead driving (rough, deep field, etc.) or if there are obstacles present, evasive action must be taken by manual operation.

The steering operation of the handle 35 by the steering actuator 206 is performed by the following configuration. An input gear 352 is provided at the bottom of the handle shaft 351 that rotates in conjunction with the steering operation of the handle 35, and an output gear 353 is provided on the steering actuator 206.

The input gear 352 and output gear 353 are mounted inside a steering gear case 354 that is located below the handle 35 and the steering actuator 206. A relay gear 355 is provided between the input gear 352 and the output gear 353 to change the transmission ratio and transmit the driving force.

The gear ratio of the input gear 352, output gear 353, and relay gear 355 is set so that the torque due to manual operation is strong even when the steering actuator 206 is operating, in order to prevent interference with manual operation of the handle 35.

This prevents the force required to manually operate the handle 35 from increasing even during automatic straight-line driving, improving operability and ensuring the avoidance of fields and obstacles that may affect driving, thereby ensuring the safety of work.

35 Handle (steering member)
100 Control device 200 GPS antenna (position information acquisition device)
205 Automatic steering device (automatic straight-line driving device)
207 Automatic straight-line setting member (operation member)

Claims (1)

A work vehicle equipped with a steering member (35) for steering a vehicle body, a position information acquisition device (200) for acquiring the position coordinates of the vehicle body, an automatic straight-line driving device (205) for operating the steering member (35) to drive the vehicle body in a straight line, and a control device (100) for controlling each part of the vehicle body,
A first operating tool is provided for acquiring a reference position that is a reference for the straight-line running of the machine body, and a second operating tool is provided for turning on and off the automatic straight-line running device (205),
The reference position includes at least two positions, namely, a first reference position (A) acquired by the first operating tool at one point in the field, and a second reference position (B) acquired by the first operating tool at another point in the field,
When the second reference position (B) is acquired by the first operating tool, if the distance from the position where the first reference position (A) is acquired is less than a predetermined distance, the second reference position (B) cannot be acquired.
A work vehicle characterized in that when the second operating device is operated while the first reference position (A) and the second reference position (B) are acquired, automatic straight-line driving by the automatic straight-line driving device (205) is turned "on," and when the second operating device is operated while the automatic straight-line driving is "on," the automatic straight-line driving device (205) is turned "off."