JP2018202929A - Automatic steering system for field work vehicle - Google Patents

Abstract

To realize autonomous straight traveling for efficient field work such as planting and plowing by automatic steering, by executing steering control to meet field conditions such as a water depth and a mud ground viscosity.SOLUTION: An automatic steering system is used for a field work vehicle, which outputs a steering signal to a steering actuator 206 for an automatic steering system 205 with a controller 100 on the basis of positional information from a positioning device 199 for autonomous traveling, and includes field recognition means 209 for detecting a field state and outputs a steering control signal from the controller 100 to the steering actuator 206 on the basis of s field state detected by the field recognition means 209.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an automatic steering device in a field work vehicle such as a rice transplanter that performs work while traveling in a field.

  In Patent Document 1 below, as an automatic steering system for a traveling work machine, a positioning unit that outputs positioning data obtained by measuring the position of the traveling work machine in a field, a route calculation unit that calculates a target travel route, and positioning data A direction calculating unit that calculates the direction of the traveling vehicle body relative to the target traveling route, a steering data output unit that outputs automatic steering data for traveling along the target traveling route, and a traveling vehicle body based on the automatic steering data. A technique for providing an automatic steering unit that generates a steering signal for steering is described.

JP 2016-24541 A

  The farm field on which the farm work vehicle travels has deep paddy fields, sticky mud, and the like, and it is difficult to travel straight ahead and requires a fine steering operation by the operator. For this reason, it is difficult to travel straight ahead only with the conventional technology that recognizes the position of the aircraft from the positioning data from the GPS satellite, calculates the direction of the traveling vehicle body with respect to the target travel route, and performs automatic steering.

  The present invention enables autonomous straight traveling by performing steering control according to field conditions such as water depth and swamp viscosity, and enables efficient field work such as planting and cultivated land by automatic steering. This is the issue.

  The problems of the present invention are solved by the following technical means.

  According to the first aspect of the present invention, in the field work vehicle that autonomously travels by outputting a steering signal to the steering actuator 206 of the automatic steering device 205 by the control device 100 based on the position information from the positioning device 199, the field for detecting the field state. Recognizing means 209 is provided and a steering control signal is output from the control device 100 to the steering actuator 206 based on the field state detected by the field recognizing means 209.

  The invention of claim 2 is a work detection sensor in which the field recognition means 209 detects the rotation of the leveling rotor 63. When the work detection sensor detects a rotation higher than a predetermined value, it detects a rotation stronger than the predetermined value and lower than the predetermined value. Then, a steering control signal is output to the steering actuator 206, which is weaker than a predetermined value, and the automatic steering device for a farm work vehicle according to claim 1 is provided.

  According to the third aspect of the present invention, the positioning device 199 is provided with a radio wave detection device 102 for detecting the strength of radio waves from the GPS antenna 200. When the radio wave detected by the radio wave detection device 102 is lower than a predetermined value, the operating speed of the steering actuator 206 is increased. The automatic steering device for a farm work vehicle according to claim 1, wherein a steering control signal for outputting a steering speed slower than a predetermined value and a traveling speed slower than a predetermined value is output.

  The invention of claim 4 is characterized in that an antenna frame 201 for attaching the GPS antenna 200 is provided above the work seat 41 of the traveling vehicle body 2, and a roof 110 is provided above the antenna frame 201. An automatic steering device for a field work vehicle.

  In the first aspect of the present invention, the field work vehicle of the present invention is automatically steered by the steering control signal output from the control device 100 to the steering actuator 206 of the automatic steering device 205. The steering control signal is the field recognition means 209. Therefore, even if the water depth of the field is deep or the viscosity of the field scene is high, automatic steering can be performed with an accurate target trajectory.

  According to the invention of claim 2, when the leveling rotor 63 that is in contact with the farm scene accurately detects the state of the field as a work detection sensor and the work detection sensor detects high speed and high speed, it is quickly transmitted with a strong steering control signal. The trajectory correction is performed to prevent wobbling, and when the work detection sensor detects low speed running at a low rotation, a weak steering control signal is used to prevent sudden trajectory correction and steer safely.

  In the invention of claim 3, when the radio wave detected by the radio wave detection device 102 is lower than a predetermined value and the position recognition of the own device in the field is low, the traveling speed is slowed and the sudden steering is not performed, so that the work can be performed safely. .

  In the invention of claim 4, since the GPS antenna 200 is provided at a high position of the antenna frame 201, it is easy to receive radio waves from the GPS and the position recognition of the own device in the field is performed well. It can block the sunlight to the worker who sits down.

The side view of a seedling transplanter. The top view of a seedling transplanter. The principal part top view of a traveling vehicle body. The principal part rear view of the control part containing a handle | steering-wheel. (A) The principal part rear view which shows the structure of the automatic steering device of a steering wheel. (B) The principal part side view which shows the structure of the automatic steering device of a steering wheel. The block diagram which shows the member relevant to various control. The flowchart which shows the control which correct | amends the acquired position coordinate according to the inclination etc. of a body. The flowchart which shows the automatic rectilinear control by an automatic steering apparatus. The flowchart which shows acquisition of the 1st and 2nd reference position by operation of an automatic rectilinear setting member, and on / off of automatic rectilinear control. The flowchart which shows erase | elimination operation of a 1st reference position and a 2nd reference position. The flowchart which shows the control which erase | eliminates a 1st reference position by handle operation after 1st reference position acquisition. The schematic diagram of the operation | work which shows a 1st reference position, a 2nd reference position, a reference line, and shows a target position. Flow chart showing the operation of the notification device and the automatic deceleration control when the stop operation of the automatic steering device is not performed after the operation of the notification device The flowchart which shows the control which erase | eliminates a 1st reference position, a 2nd reference position, and a reference line by the headland travel of an agricultural field. The perspective view of the 1st Example which attached the roof to the antenna frame. The perspective view of the 2nd Example which attached the roof to the antenna frame. The partial top view of a 2nd Example. The whole perspective view of the 3rd example which attached the roof to the antenna frame. The simplified right view of the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. In the description of the embodiment, the left and right directions in the forward direction of the aircraft are referred to as left and right, respectively, the forward direction is referred to as forward, and the backward direction is referred to as rear. However, the configuration of the present invention is not limited.

  The riding-type rice transplanter disclosed in FIG. 2 as an embodiment of the working machine of the present invention has an eight-row planting configuration, but this configuration may be used for a rice transplanter having a different number of planting strips. . As shown in FIGS. 1 and 2, the rice transplanter takes seedlings from the seedling tank 53 via the lifting link device 3 on the rear side of the traveling vehicle body 2, and seeds the seedlings in the field with a plurality of seedling planting devices 55. A working device 4 such as a seedling planting part to be planted, a seeding device for supplying seeds, or a rotary for cultivating a field is provided so as to be movable up and down, and a main body portion of the fertilizer device 5 is disposed on the rear upper side of the traveling vehicle body 2. Yes.

  First, the main frame 15 constituting the traveling vehicle body 2 will be described.

  As shown in FIG. 3, the main frame 15 includes a front beam frame 16 at the front of the fuselage, a rear beam frame 17 at the rear of the fuselage, and a central beam frame between the front beam frame 16 and the front and rear beam frames 17. 18, the front beam frame 16 and the central beam frame 18 are connected by a pair of left and right front connection frames 19, 19, and the center beam frame 18 and the rear beam frame 17 are connected by a pair of left and right rear connection frames 20, 19. Connect at 20.

  The front beam frame 16, the central beam frame 18, and the rear beam frame 17 have the left-right direction as the longitudinal direction, and the front connection frame 19 and the rear connection frame 20 have the longitudinal direction as the longitudinal direction.

  The left and right front connecting frames 19 and 19 and the rear connecting frames 20 and 20 have substantially the same left and right intervals. The left and right lengths of the central beam frame 18 and the rear beam frame 17 are longer than the left and right lengths of the front beam frame 16. Since the left and right front connection frames 19 and 19 and the rear connection frames 20 and 20 are welded at the lower part of the central beam frame 18, the left and right front connection frames 19 and 19 and the rear connection frames 20 and 20 are connected to each other. You may comprise with a metal metal square.

  In the space formed by the front beam frame 16, the central beam frame 18, and the left and right front connection frames 19, 19, a driving force is transmitted to the left and right front wheels 10, 10, the rear wheels 11, 11, the work device 4, and the like. A mission case 13 and a hydraulic continuously variable transmission (HST) 14 that outputs the driving force supplied from the engine 30 to the mission case 13 are provided.

  The left and right lifting frames 21 and 21 are provided at the rear portion of the rear beam frame 18 so as to protrude rearward at a distance narrower than the left and right distance between the left and right rear connection frames 20 and 20. The rear support frame 22 is attached to the lower part of the upper frames 21 and 21.

  Rear wheel transmission cases 11a and 11a for driving the left and right rear wheels 11 and 11 of the traveling vehicle body 2 are respectively provided on the left and right sides of the rear support frame 22, and the elevating link mechanism is provided above the rear support frame 22. The left and right link frames 23, 23 that support 3 are provided facing upward.

  The lift link mechanism 3 is provided with a pair of left and right lower link arms 24, 24 on the lower side of the left and right link frames 23, 23 between the left and right, and a lift cylinder 25 between the left and right of the left and right lower link arms 24, 24. And an upper link arm 26 is provided above the elevating cylinder 25. Note that 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 traveling vehicle body 2 are attached to the front side of the work apparatus 4.

  Further, front transmission cases 10a and 10a that respectively transmit to the left and right front wheels 10 and 10 of the traveling vehicle body 2 are provided in front of the left and right ends of the central beam frame 18 and on the left and right outer sides of the left and right front connection frames 19 and 19, respectively. At the same time, 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 and 27, respectively. The left and right extension frames 27, 27 have a longitudinal direction as a longitudinal direction.

  Further, a central connecting frame 28 in the front-rear direction is provided below the central beam frame 18, the rear beam frame 17, and the rear support frame 22, and between the front and rear of the central beam frame 18 and the rear beam frame 17 and the left and right rear portions. Front and rear support plates 29 and 29 for supporting the engine 30 are provided between the left and right sides of the connection frames 20 and 20.

  The front and rear support plates 29, 29 are respectively provided with receiving plates 29a for receiving the engine 30 on both the left and right sides of the central connecting frame 28.

  The left and right auxiliary frames 31, 31 are provided on the left and right sides of the front and rear support plates 29, 29 so as to pass below the rear beam frame 17 and protrude rearward. Are connected by a rear auxiliary frame 32 in the left-right direction. The rear end portions 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 configured as described above. Of the main frame 15, the floor on which an operator rides the front-rear width from the front beam frame 16 to the rear beam frame 17, and the left-right widths of the left and right front connection frames 19, 19 and the rear connection frames 20, 20. Cover in step 33. The floor tape 33 is formed integrally to improve strength and reduce the number of parts, or is configured so as to be divided into a front side and a rear side, a left side and a right side, and easy to attach and detach.

  In the above, as shown in FIG. 3, the periphery of 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 and 27 are not covered with the floor step 33 but exposed. At this time, the floor step 33 may be enlarged to cover the entire main frame 15, but the floor step 33 may be shared between aircrafts having different sizes and number of planting work. The left and right extension steps 34, 34 are arranged on the left and right sides of each.

  With the above configuration, the main frame 15 is configured by connecting a plurality of frame structural bodies, so that the strength is improved as compared with the conventional structure.

  In addition, the central connection frame 28 is disposed below the front and rear support plates 29 and 29 on which the engine 30 is mounted, and the front and rear support plates 29 and 29 are connected to the left and right rear auxiliary frames 32 and 32, thereby allowing heavy loads. The engine 30 can be held firmly.

  As shown in FIGS. 1 and 2, on the front side of the traveling vehicle body 2, a steering wheel 35 for steering the airframe, a speed change operation lever 36 for operating the continuously variable transmission 14 and the work device 4, and traveling transmission of the traveling vehicle body 2 are provided. A bonnet 39 having an auxiliary transmission operating lever 37 for operating an auxiliary transmission switching device (not shown) for switching between and a control panel 38 for operating each part of the machine body is provided. A front cover 40 that can be opened and closed is provided on the front side of the bonnet 39. Inside the front cover 40 is a fuel tank, a battery, the left and right front wheels 10, 10 for steering the handle 35, and left and right front wheel transmission cases. An interlocking mechanism (not shown) for rotating the lower side of 10a and 10a is provided.

  Further, in front of the front cover 40, various information such as the working state of the working device 4 and the reduction of work materials consumed during the work, and the operation and non-operation of the automatic steering device 205, which will be described later, are indicated by lighting LEDs. A center mascot 70 for display is provided. The center mascot 70 includes a work display unit 71 disposed on the lower side and the rear side, and an automatic rectilinear display unit 72 disposed on the upper side and the front side in a side view.

  An engine cover 30a that covers the upper side and the side 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 above the engine cover 30a. Is provided.

  Furthermore, the fertilizer application device 5 is loaded on the rear side of the work seat 41, specifically on the rear end side of the main frame 15. The driving force of the fertilizer application device 5 is transmitted by a fertilizer transmission mechanism 5a arranged toward the fertilizer application device 5 from the left and right sides of the left and right rear wheel transmission cases 11a.

  The front side of the transmission case 13 has a front transmission shaft (not shown) for transmission to the left and right front wheel transmission cases 10a, 10a, and the rear part of the transmission case 13 has transmission to the left and right rear wheel transmission cases 11a, 11a. Left and right drive shafts 42, 42 are provided. Side clutch mechanisms 43, 43 for turning on and off the transmission to the left and right drive shafts 42, 42 are arranged on the upper side in the transmission direction from the left and right drive shafts 42, 42. When the traveling vehicle body 2 is turned, the side clutch mechanism 43 located inside the turn is turned off, and the transmission to the rear wheel 11 inside the turn is stopped.

  As shown in FIG. 3, left and right clutch on / off shafts 44, 44 are provided in the vertical direction in the vicinity of the left and right center of the rear side of the transmission case 13, and the upper part of the left and right clutch on / off shafts 44, 44 is directed to the outside of the aircraft. Clutch on / off arms 45, 45 are provided. Further, side clutch pedals 43a and 43a for turning on and off the left and right side clutch mechanisms 43 and 43 are provided at the front lower portion of the control seat 41 and on the left and right sides.

  Further, as shown in FIGS. 1 and 2, a center float 62C and left and right side floats 62L and 62R that touch the farm scene and slide are provided below the work device 4, and the center float 62C and the left and right side are provided. A leveling rotor 63 is provided on the front side of the machine body relative to the floats 62L and 62R to level the unevenness of the field scene. The driving force to the leveling rotor 63 is transmitted by a leveling shaft 65 provided on the left and right rear wheel transmission case 11a. Further, the rear wheel transmission case 11 a on the left and right sides is provided with a leveling clutch 66 for turning on and off the transmission to the leveling rotor 63.

  The leveling rotor 63 is provided with a work detection sensor 209 as a field recognition means. When the water depth of the field is deep or the viscosity of the field is high, the leveling rotor 63 rotates slowly, and when the high-speed driving or the field scene is rough, the rotation speed increases. The detection result of 209 is input to the control device 100, and the steering control signal to the steering actuator 206 of the automatic steering device 205 is adjusted. For example, when the leveling rotor 63 rotates rapidly, the water depth is shallow, the farm scene is hard, and the traveling speed is high, so the steering angle is controlled to be large.

  The center float 62C is provided with a rotation potentiometer 64 for detecting 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. The controller 100 extends and retracts the lift cylinder 25 to vertically rotate the lift link mechanism 3 so that the vertical height of the work device 4, that is, the work position corresponds to the depth of the field.

  When performing work such as seedling planting, seed sowing work, topdressing or weeding after seedling growth in the field using the working device 4, the traveling vehicle body 2 from one side of the field to the other side. It is common to drive straight ahead. However, the traveling vehicle body 2 may gradually move in a direction shifted when the wheels turn in a direction deviating from the straight traveling direction due to unevenness of the tiller in the field or the viscosity of the topsoil. Further, depending on the operator's maneuvering technique, the traveling vehicle body 2 may not be adjusted to the straight traveling direction and may be moved in a direction deviating from the straight traveling.

  As a result, the trajectory of planting and sowing of seedlings, weeding, topdressing, etc. is oblique, and the place where seedlings can be planted and sowed becomes an empty space. It becomes necessary to sow, causing extra labor to the operator, and the spacing between the seedling planting and seeding strips becomes narrower than the strips of the working device 4, resulting in poor ventilation and pest damage. Sometimes. Or, when performing post-planting and sowing work, such as weeding work or top dressing work, the seedling is crushed, leading to a decrease in yield, and maneuvering so as not to crush the seedling, Problems that reduce work efficiency can occur.

  In order to solve these problems, it is conceivable to install a so-called automatic straight traveling system that automatically steers the traveling vehicle body 2 and maintains a straight traveling posture without depending on the hand of the operator.

  First, as shown in FIGS. 1 and 2, an antenna frame 201 to which a GPS (GNSS) antenna 200 is attached is provided on the traveling vehicle body 2. The antenna frame 201 has left and right bases attached to left and right antenna stays 202, 202 provided on the front side of the main frame 15. The front frame 201a has a portal shape when viewed from the front, and the left and right central portions of the front frame 201a. The rear frame 201b is directed rearward and toward the left and right central portion of the rear side of the traveling vehicle body 2. It is assumed that the bonnet 32 and the control seat 41 are located behind the space portion of the gate-shaped front frame 201a.

  The vertical height of the antenna frame 201 is the highest in the aircraft. The upper end portion of the antenna frame 201 is positioned about 2.5 to 3.5 m from the ground surface in order to prevent the worker from hitting his head while standing on the floor step 33 and to improve reception accuracy. Shall.

  Thus, the operator can easily move on the floor step 33, work efficiency is improved, and the GPS antenna 200 can be separated upward from the ground surface, so that reception accuracy is improved.

  The GPS antenna 200 is mounted in the vicinity of the connecting portion between the front frame 201a and the rear frame 201b. The connecting portion between the front frame 201a and the rear frame 201b is near the front and rear of the bonnet 32 and the control seat 41, and is near the center of the traveling vehicle body 2 in the front-rear direction.

  As described above, the GPS antenna 200 is attached in the vicinity of the center of the aircraft in the front-rear and left-right directions, so that the coordinates of the acquired aircraft are unlikely to be separated from the actual aircraft position, and the straight traveling position by the automatic linear system The setting becomes appropriate and the work accuracy is improved.

  Further, since the control seat 41 is positioned behind the space portion of the front frame 201a, the antenna frame 201 can be prevented from blocking the operator's field of view, so that visibility is improved and alignment before straight running is accurate. At the same time, since the state of the field and obstacles ahead of the machine body can be found early, it is possible to switch to manual operation by the operator and to suppress the shift of the work position safely.

  The GPS antenna 200 may be a single positioning method, a DGPS (relative positioning) method, an RTK (interference positioning) method, or the like that is suitable for the region where the work is performed.

  However, if the ground height of the GPS antenna 200 fluctuates due to the tilt or vibration of the fuselage, the coordinate position different from the actual fuselage position is measured, the reception accuracy is lowered, and the fuselage runs in a direction deviating from straight ahead. Problem arises.

  In order to prevent this, as shown in FIG. 6, in addition to the GPS antenna 200, an IMU (Inertial Measurement Device) 203 is provided. The IMU 203 is 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 the traveling vehicle body 2 is not inclined. The position coordinates are corrected by the control device 100.

  Note that the height from the ground surface to the GPS antenna 200 is determined by measuring the behavior of the traveling vehicle body 2 such as the inclination with a triaxial acceleration sensor and an angular velocity sensor built in the IMU 203.

  In addition to this, a direction sensor 204 is provided in order to make the control device 100 more surely determine whether or not the traveling direction of the aircraft by the automatic linear system is correct.

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

  Thereby, since the course of the airframe can be determined by the measured direction, the accuracy of the straight traveling is further improved.

  The position information acquired by the GPS antenna 200 is corrected by the control device 100 based on information detected by the IMU 203 and the direction sensor 204. The control device 100 compares the current position information with the previously acquired position information, and if the difference in position information exceeds the allowable range, the left and right front wheels 10 are returned to return the aircraft to the straight traveling position. , 10 are steered in the left-right direction.

  In order to automate the steering of the left and right front wheels 10 and 10 or the pivoting of a crawler or the like, an automatic steering device 205 for rotating the handle 35 by a steering actuator 206 is provided. As shown in S6 to S9 in FIG. 8, the automatic steering device 205 determines 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 acquired previously. Based on this, the operating amount of the steering actuator 206 is changed, so that the handle 35 is turned to the left and right so that the airframe is directed to the straight traveling position, and when the straight traveling position is reached, the steering actuator 206 is stopped and the handle 35 is automatically operated. Steering is stopped. The rudder actuator 206 is constituted by an electric or hydraulic motor or a cylinder.

  In addition, when the radio wave detection device 102 for detecting the radio wave from the GPS antenna 200 is provided and the received radio wave is lower than a predetermined value, the traveling speed is lowered and the steering angle control to the steering actuator 206 is reduced to reduce the work. To be safe. When the received radio wave recovers to a predetermined value, the traveling speed and the steering angle control to the steering actuator 206 are restored.

  With the above configuration, the steering wheel 35 is automatically steered in accordance with the difference in the X coordinate of the calculated position information, and the machine body can be automatically adjusted to the straight traveling position. It is prevented from shifting and it is difficult to generate a place where work is not performed in the field. Thereby, it is not necessary to manually perform the work afterwards in a place where the work is not performed, and the labor of the worker is reduced.

  In addition, since it is possible to prevent the work position in the previous process and the current work line from overlapping, it is possible to prevent excessive consumption of work materials such as seedlings, seeds, and fertilizers, thereby reducing work costs. At the same time, the occurrence of poor growth due to excessive supply of work materials is prevented.

  The tractor, seedling transplanter, and sowing machine equipped with the tiller travel to the field end of the work strip, turn about 180 degrees, and move to the next work strip. If the automatic rectilinear system is operating during turning, the steering actuator 206 may be operated by judging that the airframe is deviated from the position where it should go straight, and the turning trajectory may be disturbed. Therefore, it is necessary that the automatic straight traveling system be turned off when the aircraft is turned. It is conceivable that the automatic rectilinear system is turned off when the handle 35 is turned. However, depending on the state of the field, the advancing direction of the machine body is greatly shifted, and the operator turns the handle 35 to avoid an obstacle. Since the automatic linear system is turned off when the operation is larger than the operation, the operator has to turn the automatic steering system on again in the middle of the straight movement. There is a problem that the airframe travels while the work position is shifted without noticing that it is turned off, and the work accuracy decreases.

  Although it is conceivable to turn on the automatic rectilinear system by returning the handle 35 from turning to straight running, when returning from turning to straight running, in order to align the aircraft with the straight running position in the next work line, It is necessary to perform a steering operation. If the automatic steering system is turned on during this operation, the steering actuator 206 is activated when the control device 100 determines that the aircraft has deviated from the straight travel position, so that the position of the aircraft matches the position where the vehicle should travel straight ahead. There is a problem that makes it impossible.

  An automatic rectilinear system capable of preventing the occurrence of this problem and causing the aircraft to travel straight in an appropriate direction and operate in an appropriate section will be described with reference to FIGS. 6 and 8 to 11.

  In addition, the position coordinate of the traveling vehicle body 2 in the forward / backward direction is defined as the Y coordinate, and the direction coordinate orthogonal to the forward / backward direction of the traveling vehicle body 2, that is, the position coordinate in the lateral direction is defined as the X coordinate.

  First, the traveling vehicle body 2 is caused to acquire the coordinates of one side of the field that is the starting point of the automatic linear advance and the other side of the field that is the end point of the automatic linear advance, and the automatic linear advance setting member 207 that turns on and off the automatic linear system. Is provided. The automatic rectilinear setting member 207 is mounted with at least one member that can be operated in at least two directions such as up and down direction, left and right direction, pushed state and return state, or two or more operation members. .

  In this application, as shown in FIG. 4, a finger up lever that can be operated in the vertical direction is mounted as the automatic linear advance setting member 207, but a toggle switch, a push switch, a joystick, or the like may be used.

  Thereby, the number of parts can be reduced, and the acquisition operation of the reference position (the first reference position A and the second reference position B) and the on / off operation of the automatic steering device 205 are automatically performed with one hand on the same side. Since the rectilinear setting member 207 may be operated, the operability is improved.

  As shown in FIG. 4, when the automatic linear advance setting member 207 is operated in the first direction W <b> 1, in this application, upward of the aircraft, the GPS antenna 200 is acquired at the operated position, and the detection results of the IMU 203 and the orientation sensor 204 are obtained. Is used to record the position coordinates calculated by the control device 100. The operation of the automatic linear advance setting member 207 in the first direction W1 corresponds to the operation of the reference position acquisition member.

  When the automatic linear advance setting member 207 is operated, when there is no record of other position coordinates, the calculated position coordinates are recorded as the first reference point A, and when the first reference point A is recorded, The calculated position coordinates are recorded as the second reference point B. When the automatic linear advance setting member 207 is operated while the first reference point A and the second reference point B are recorded, the position coordinates are not recorded.

  It should be noted that when the automatic straight traveling cannot be performed accurately during the work in the field, it is necessary to acquire the first reference point A and the second reference point B again. As shown in FIG. Is a setting in which the recorded first reference point A and second reference point B are erased when the automatic rectilinear setting member 207 is operated in the first direction W1 for a predetermined time (eg, 2 to 3 seconds). It is good to do. Alternatively, a record erasing button (not shown) may be provided that deletes the first reference point A and the second reference point B when operated.

  The first reference point A and the second reference point B, which are the reference positions for the straight traveling of the automatic straight traveling system, are smaller in the X coordinate as the distance is shorter, but if the distance between the two points is shorter, the automatic straight traveling is used. Even without it, it is possible to run straight ahead. In addition, when the distance between the two points becomes short, it is conceivable that the operator unintentionally touches the automatic linear advance setting member 207 and acquires the second reference point B.

  In order to prevent the occurrence of this problem, when the second reference point B is acquired by operating the automatic linear advance setting member 207, the distance from the position where the first reference point A is acquired is less than a predetermined distance, for example, 8 to 12 m. If it is less, the control device 100 deletes the second reference point B and does not record it. Thereafter, when the automatic linear advance setting member 207 is operated again and the distance from the position where the first reference point A is acquired is equal to or greater than a predetermined distance, the control device 100 records the second reference point.

  As shown in FIG. 11, with the first reference point A acquired, the handle 35 was operated to a predetermined amount or more within a predetermined time without acquiring the second reference point B, and the traveling vehicle body 2 was turned. At this time, the control device 100 deletes the recorded first reference point A. Thereafter, when the automatic linear advance setting member 207 is operated in the first direction W1, the control device 100 records the position coordinates of the place acquired by the GPS antenna 200 as the first reference point A, and the first reference point A is recorded. The line connecting the Y coordinate of the point A and the Y coordinate of the second reference point B may be prevented from becoming a straight line.

  Accordingly, the first position is set to a predetermined position on one end and the other end of the field, for example, a position where the traveling vehicle body 2 starts turning after finishing the straight traveling, and a position where the work device 4 is lowered after the turning ends to start the straight traveling. The reference point A and the second reference point B can be set, the automatic linear movement system is operated at a position where the work device 4 is lowered and the vehicle travels straight, and the work position does not shift in the left-right direction with respect to the traveling direction. Accurate work is possible.

  Further, since it is possible to prevent the second reference point B from being different from the position to be actually set due to an erroneous operation by the operator, there is no need to re-acquire the first reference point A and the second reference point B in the next work item. In addition, the number of work strips using automatic straight travel can be increased, and the work accuracy in the field can be further improved.

  Note that, in the work strip to be worked for the first time after entering the field, the above-mentioned first reference point A and second reference point B are obtained by operating the automatic linear advance setting member 207 in the first direction W1 at a predetermined position. Therefore, the operator operates the handle 35 and makes the machine travel straight ahead without using automatic straight travel.

  As described above, when the first reference point A and the second reference point B are acquired by operating the automatic linear advance setting member 207, the reference that connects the Y coordinates of the first reference point A and the second reference point B. The line R becomes a reference line for automatic straight travel, and it is determined whether or not the X coordinate of the position coordinate of the aircraft that is running matches the X coordinate of the line that is the standard for automatic straight travel. For example, by automatically steering the handle 35 in the matching direction by the automatic steering device 205, automatic straight traveling can be realized.

  The above-mentioned automatic straight traveling is started by operating the automatic linear advance setting member 207 in the second direction W2, in the present application, downward in the aircraft body, with the first reference point A and the second reference point B recorded. Is done. When the automatic rectilinear 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, and operates the steering actuator 206. The control of rotating the steering wheel 35 in the left-right direction and moving the traveling vehicle body 2 to a position where the traveling body 2 should travel straight is started. The operation of the automatic linear advance setting member 207 in the second direction W2 corresponds to the operation of the on / off member.

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

  In addition, when the traveling vehicle body 2 arrives at a place that coincides with the Y coordinate of the first reference point A or the second reference point B, the automatic linear control may be terminated.

  As described above, the automatic rectilinear control is terminated by turning the handle 35 or reaching the vicinity of the starting point of the turning traveling at the end of the field. Since the position at which the traveling vehicle body 2 turns is close to the end of the field, if the worker performs work other than maneuvering while relying on automatic straight-ahead control, if the turning operation is delayed, the seedling is placed at an unscheduled position. As planting is performed, the traveling vehicle body 2 moves to the end of the field, and it is necessary to move backward to the position where the vehicle turns. This causes a problem that work efficiency is lowered.

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

  In order to prevent this problem, as shown in FIGS. 6 and 13, a work detection sensor 209 is provided to detect the turning on and off of the leveling rotor 63 and the number of rotations by turning on and off (stopping) the leveling clutch 66. When the work detection sensor 209 detects the entry (operation) of the leveling rotor 63, the control device 100 acquires target position coordinates (end reference position) that are position coordinates (X coordinate and Y coordinate) of the traveling vehicle body 2. To do. Note that at least two target position coordinates can be simultaneously held in the control device 100 or a memory area associated with the control device 100.

  The target position coordinates (end reference position) obtained by the work detection sensor 209 are obtained by raising or lowering the work device 4 instead of turning the leveling rotor 63 on and off, turning on and off the transmission to the work device 4, and the handle 35. It is good also as a structure performed on condition of the above-mentioned turning start steering or turning end steering.

  When the automatic steering device 205 is operated to cause the traveling vehicle body 2 to travel straight ahead automatically in the work line that follows the work line from which the position coordinates have been acquired, the control device 100 determines the current position coordinates that the GPS antenna 200 acquires. The distance from the Y coordinate to the Y coordinate of the target position coordinate acquired in the immediately preceding work line (the latest work line) is calculated sequentially. At this time, the control device 100 may be configured to correct the X coordinate of the target position coordinate to the X coordinate of the current position coordinate.

  When the traveling vehicle body 2 reaches the 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 traveling vehicle body 2 is approaching the farm field end, and the automatic linear advance setting member 207 In order to notify the operator that it is necessary to end the automatic linear advance control by operating in the second direction W2, and a configuration in which the notification device 208 is operated to display a numerical value or a character on a buzzer, a lamp, or a screen. To do.

  Note that numerical values and characters are displayed on the notification device 208 by displaying information on a configuration in which a display panel (not shown) is provided on the traveling vehicle body 2 or an information terminal (smart phone, tablet, etc.) carried by an operator. The structure to be made can be considered.

  It should be noted that since the distance between the traveling vehicle body 2 and the target position cannot be calculated in a work item for which the target position coordinates have not been acquired, the operator visually confirms the field edge and determines that automatic straight-ahead control is unnecessary. It is necessary to operate the automatic linear advance setting member 207.

  For the distance from the current position coordinates to the target position coordinates, rear wheel rotation sensors 210 and 210 for detecting the rotation of the left and right drive shafts 42 and 42 to the left and right rear wheels 11 and 11 are provided, and the leveling rotor 63 Based on the number of rotations detected by the rear wheel rotation sensors 210, 210 from the position where the wheel is turned on, the control device 100 calculates the movement distance, and the movement distance and the Y coordinate position of the position where the leveling rotor 63 is turned on are calculated. The distance may be calculated, and the notification device 208 may be activated if it is within a predetermined distance.

  However, even if the notification device 208 is activated, the traveling vehicle body 2 cannot be turned at an appropriate position unless the operator notices it and terminates the automatic linear advance control. To cope with this, the traveling vehicle body 2 moves forward without operating the automatic linear advance setting member 207 in the second direction W2 for a predetermined distance (for example, 2 to 5 m) after the notification device 208 is activated. When traveling, the control device 100 rotates the trunnion shaft 14a of the continuously variable transmission 14 to decelerate the traveling vehicle body 2.

  Alternatively, instead of the distance, the traveling vehicle body 2 is not operated in the second direction W2 for a predetermined time (for example, 2 to 5 seconds) after the notification device 208 is activated without being operated in the second direction W2. When traveling forward, the control device 100 decreases the output of the continuously variable transmission 14 and decelerates the traveling vehicle body 2.

  The vehicle body 2 is decelerated by operating the HST servo motor 211 that rotates the trunnion shaft 14a of the continuously variable transmission 14 via a trunnion arm (not shown), and rotating the trunnion shaft 14a to the deceleration side. Is done by letting

  Thereby, since the traveling speed of the traveling vehicle body 2 decreases when approaching the farm field end, it is possible to make the operator recognize that the turning position of the farm field end is approaching, and it is possible to perform a turn traveling with an appropriate trajectory. Therefore, it is possible to prevent the working device 4 from performing redundant ground work on the four sides of the outer periphery of the field, so-called headland, and consuming work materials (seedling, fertilizer, medicine, etc.) excessively.

  In addition, since the position where the leveling work is started after turning the ground leveling rotor 63 can be adjusted to the position where the leveling work is completed before the turning, the occurrence of a place where the leveling work is not performed by the leveling rotor 63, and Generation | occurrence | production of the location where the ground work by the working apparatus 4 is not performed is prevented. This prevents the occurrence of problems such as disturbing planting depth of seedlings, different fertilizer penetration conditions, and disturbed traveling at locations where leveling work has not been performed, and where ground work has not been performed. Therefore, it is not necessary for the worker to perform the work manually, and the labor of the worker is reduced.

  In the automatic deceleration described above, the traveling speed gradually decreases with the passage of time, and if the control configuration is gradually decelerated, the ground work accuracy by the work device 4 and the leveling accuracy of the leveling rotor 63 are reduced. Is prevented from being shaken.

  Or if it is set as the control structure which carries out rapid deceleration once after the start of automatic deceleration, or several times for every predetermined time, it will become easy for an operator to notice approach of an agricultural field end by the shaking of the traveling vehicle body 2. FIG.

  Further, when the automatic linear advance setting member 207 is operated to cancel the automatic linear advance control within a predetermined time (second predetermined time) during which automatic deceleration control is performed, the control device 100 maintains the traveling speed at that time. It is good also as composition to do. Thereby, since the work traveling does not stop, it is possible to promptly shift to the turning traveling at the end of the field and to prevent the work efficiency from being lowered.

  Alternatively, the control device 100 operates the HST servo motor 211 of the continuously variable transmission 14 to shift to the preset traveling speed or the traveling speed at the time when the automatic deceleration is started, and the trunnion shaft 14a. It is good also as a structure which rotates to the acceleration side.

  Since the traveling speed is automatically increased, it is not necessary for the operator to increase the traveling speed by operating the speed change lever 36, so that the operability is improved.

  In addition to the operation of the notification device 208, the automatic deceleration control of the traveling vehicle body 2 is expected to allow the traveling vehicle body 2 to recognize the field edge, specifically, the turning position near the field edge. There is a possibility that the user may not be aware of the automatic deceleration of the traveling speed because he / she is immersed in another work or the worker faints.

  Therefore, the automatic deceleration control of the traveling vehicle body 2 is performed until the continuously variable transmission 14 is in a neutral state in which neither the forward speed nor the reverse speed is increased or decreased. At this time, the engine 30 is not stopped. As a result, the traveling vehicle body 2 can be stopped on the spot, so that the vehicle body is prevented from moving forward until the vehicle body comes into contact with the field edge, so-called straw, and the vehicle body is damaged or the distance to which the vehicle body is moved backward to return to work is reduced. It can be suppressed.

  When the travel of the traveling vehicle body 2 automatically stops due to the approach to the farm field end, the control device 100 causes the continuously variable transmission when the shift operation lever 36 for operating the traveling speed of the traveling vehicle body 2 to increase / decrease and to move back and forth is returned to the neutral position. A state in which an increase / decrease operation of the traveling speed by the device 14 is accepted. Then, when the shift operation lever 36 is operated to the forward side, the traveling of the traveling vehicle body 2 is resumed. As a matter of course, in the state where the auxiliary transmission operation lever 37 is operated to the neutral position and the driving force is not transmitted to the traveling system, the traveling is continued until the auxiliary transmission operation lever 37 is operated to the position where the traveling transmission is performed. Not started.

  The reference line R connecting the first reference point A and the second reference point B, and the first reference point A and the second reference point B, which serve as a reference for the above-described automatic linear advance control, goes straight from one end of the field to the other end. Necessary for work travel and when traveling straight from the other end of the field to one end.

  However, although the work traveling on the four sides of the field, the so-called headland, is a straight traveling work traveling, there is one working side that has a different traveling direction from the straight traveling working traveling, and the reference line R is used for the working side. However, automatic straight control cannot be performed.

  In addition, when the machine body is moved to the loading platform of a transfer truck or the like in a barn or the like outside the field, the automatic steering device is erroneously operated in the second direction W2 by mistake. When 205 is in an operable state, when the aircraft is moved, the X coordinate of the reference line (R) and the X coordinate of the aircraft do not coincide with each other, and it is determined that the vehicle is deviated from the straight traveling position. It may happen that the steering wheel 35 is automatically steered. As a result, the course of the aircraft becomes a position deviated from the course that should be traveled, and extra effort is required for loading and storing the aircraft.

  In order 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 aircraft leaves the field. As shown in FIGS. 6 and 14, when the traveling vehicle body 2 travels on three sides including at least one traveling direction orthogonal to the traveling direction in which the traveling vehicle 2 travels in a straight line, the headland work is performed. The control device 100 deletes the first reference point A, the second reference point B, and the reference line R.

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

  Accordingly, the first reference point A, the second reference point B, and the reference line R can be deleted while the vehicle is traveling in the field. Even if operated, automatic straight travel is not performed, and traveling in a direction deviating from the planned traveling direction is prevented, work efficiency is prevented from being lowered, and work safety is improved.

  In addition, when the aircraft is moved to another field, the first reference point A, the second reference point B, and the reference line R are not recorded, so that the automatic operation is performed based on the reference line R that is not suitable for the working field. Since it is possible to prevent the straight-ahead control from being performed, the accuracy of the automatic straight-ahead is improved.

  In addition, when moving out of the field, the sub-shift operation lever 37 is operated to the traveling position in order to move to a transfer truck or move to a barn in a short time. A sub shift position detecting switch 37a for detecting the operation of the sub shift operating lever 37 to the travel position is provided. When the sub shift position detecting switch 37a detects that the sub shift operating lever 37 is operated to the travel position, the first shift position detecting switch 37a is operated. The reference point A, the second reference point B, and the reference line R may be deleted.

  The first reference point A, the second reference point B, and the reference line R are deleted based on the operation of the sub-shift operation lever 37 to a travel position that is not used in the field, so that the first reference point during headland travel When A, the second reference point B, and the reference line R are not deleted, they can be deleted with certainty, so automatic straight-ahead control is not performed during movement of the traveling vehicle body 2 or work on another field, A decrease in work accuracy is prevented.

  In addition, since the first reference point A, the second reference point B, and the reference line R can be prevented from being erroneously deleted in the field due to an erroneous operation of the auxiliary transmission operation lever 37, the first reference point A and the second reference point It is prevented that the automatic straight travel cannot be used in the work line in which the point B is reacquired, and the work accuracy is improved.

  Alternatively, when the traveling vehicle body 2 is in a forwardly inclined posture more than a predetermined angle (for example, 10 to 15 degrees) using the IMU 203 or the inclination sensor 212 that detects the inclination of the traveling vehicle body 2 in the front-rear and left-right directions, the control device Reference numeral 100 may be configured to delete the first reference point A, the second reference point B, and the reference line R.

  When leaving the field, the traveling vehicle body 2 that passes through the field entrance and exit is in a forward-upward tilt posture at an angle that cannot be approximated during work, so when this tilt angle is detected, it is time to leave the field. I can judge.

  Accordingly, when the first reference point A, the second reference point B, and the reference line R are not deleted during traveling on the headland, it can be surely deleted. In some cases, automatic straight-ahead control is not performed, and a reduction in work accuracy is prevented.

  Depending on the field and the contents of the work, the traveling vehicle body 2 may be moved backward and exit from the entrance. Therefore, the first reference point A and the second reference point are based not only on the front rising inclination angle but also on the rear rising inclination angle. The control configuration may be such that B and the reference line R are deleted.

  Even when the traveling vehicle body 2 is automatically straight traveling by the automatic steering device 205, when work material replenishment work consumed by the work device 4 or the like, or when some problem occurs in the machine body or the field, etc. The worker needs to stop traveling. This travel stop operation is performed by operating the shift operation lever 36 to the neutral position to neutralize the continuously variable transmission 14, depressing the brake pedal to apply the brake, depressing the side clutch pedal 43a, and disengaging the side clutch 43. A method of setting the state is conceivable.

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

  As a result, when the traveling stop is canceled by, for example, operating the shift operation lever 36 forward, releasing the operation of the brake pedal or the side clutch pedal 43a, it becomes possible to immediately return to the automatic straight traveling, thereby improving the work efficiency. Is prevented.

  However, if the steering wheel 35 is manually steered while the vehicle is stopped, or the automatic steering device 205 is activated and the steering wheel 35 is automatically steered, the traveling direction at the time of resuming the automatic straight traveling is deviated from the traveling direction at the time of stopping. The traveling direction of the traveling vehicle body 2 may not be linear.

  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, the revolution of the GPS satellite, and the like, and are different from the positions where the actual traveling vehicle body 2 exists. Coordinates may be acquired, and it is easy to be mistaken for being at a position away from the reference line R.

  In order to prevent this, a lever potentiometer 36a for detecting the operation position of the speed change operation lever 36 and a depression detection switch 213 for detecting depression of a brake pedal or a clutch pedal are provided, and an operation for stopping traveling during automatic straight traveling is provided. When detected, the control device 100 is configured not to reflect the steering operation of the handle 35 or to prevent the handle 35 from moving.

  The configuration not reflecting the steering operation of the steering wheel 35 means that the steering actuator 206 is not operated even if the X coordinate of the position coordinate of the traveling vehicle body 2 at the time of stopping deviates from the X coordinate of the reference line R by a predetermined value or more. .

  Further, the configuration in which the handle 35 is not moved means that the operating torque of the steering actuator 206 is increased and the handle is locked.

  With the above-described configuration, it is possible to prevent the traveling direction from deviating after traveling is resumed, so that work traveling is performed in a straight line, and work accuracy is improved.

  The steering wheel 35 is automatically steered by the steering actuator 206 during automatic straight traveling, but the state of the field on the path is not suitable for automatic straight traveling (rough, deep field depth, etc.), and there is an obstacle. In situations such as doing this, it is necessary to take an avoidance action 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 below 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 the output gear 353 are housed in a steering gear case 354 disposed 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, the output gear 353, and the relay gear 355 is a gear ratio that increases the torque due to manual operation even when the steering actuator 206 is operating so as to prevent manual operation of the handle 35. To do.

  As a result, it is possible to prevent an increase in the force required for manual operation of the handle 35 even during automatic straight traveling, thereby improving operability and reliably avoiding fields and obstacles that may affect traveling. Therefore, work safety is ensured.

  In FIG. 1, a depth sensor 103 made of an ultrasonic sensor is attached to the traveling vehicle body 2 in front of the front wheel 10 toward the field scene to detect the distance to the water storage surface, or the field fertility is detected on the front wheel 10. The energization sensor 104 is provided to detect the fertility of the field, or the temperature sensor 105 is provided on the traveling vehicle body 2 to detect the outside air temperature, and the operator displays the information on the control panel 38. Make it easier to recognize the state of the field. If the temperature sensor 105 detects an abnormally low temperature, it is determined that there is no water in the field and the control output to the steering actuator 206 is weakened. If the detection value of the energization sensor 104 is high, the field is determined to be soft and the steering actuator 206 control output is strengthened.

  Next, the structure which provides the roof 110 which covers the upper part of the work seat 41 is demonstrated with reference to FIGS.

  In the first embodiment of FIG. 15, a resin-molded roof 110 is attached to left and right attachment pieces 95L and 95R provided on the front frame 201a of the antenna frame 201 and a rear attachment frame 96 of the rear frame 201b. The front-rear width of the roof 110 is the distance between the handle 35 and the fertilizer application device 5, and the left-right width is slightly narrower than the left-right width of the traveling vehicle body 2. The GPS antenna 200 is located above the roof 110.

  In the second embodiment of FIG. 16, the left and right side roof arms 111L and 111R are pivotally supported on the upper left and right brackets 114 of the front frame 201a, and are fixed to the fixing holes of the bracket 114 with the lock pins 113 so that the left and right open / close can be fixed. A curtain-shaped roof 110 is stretched between the rear frame 201b and the central rod 201bc, and the left and right side roof arms 111L and 111R are placed along the central rod 201bc when not in use to close the roof 110.

  In the third embodiment of FIG. 18, left and right roof columns 115L and 115R are provided on a side step frame 116 to which a side step 117 is attached to the side of the floor step 33, and a resin-molded roof 110 is provided above the left and right roof columns 115L and 115R. As shown in FIG. 19, the left and right roof columns 115L and 115R are bent rearward at the upper and lower intermediate portions so that the roof 110 can be stored low.

  The present invention is applicable not only to a riding rice transplanter but also to various field work machines such as a seeder capable of automatic traveling equipped with a field work device.

2 traveling vehicle body 41 work seat 100 control device 102 radio wave detection device 110 roof 199 positioning device 200 GPS antenna 201 antenna frame 205 automatic steering device 206 steering actuator 209 field recognition means (work detection sensor)

Claims (4)

  Based on the position information from the positioning device (199), the control device (100) outputs a steering signal to the steering actuator (206) of the automatic steering device (205) to detect the field condition in the field work vehicle that autonomously travels. An agricultural field provided with an agricultural field recognition means (209) and outputting a steering control signal from the control device (100) to the steering actuator (206) based on the agricultural field state detected by the agricultural field recognition means (209) Automatic steering device for work vehicles.   The field recognition means (209) is a work detection sensor for detecting the rotation of the leveling rotor (63). When the work detection sensor detects a rotation higher than a predetermined value, it is stronger than a predetermined value and predetermined when a rotation lower than the predetermined value is detected. The automatic steering device for a farm work vehicle according to claim 1, wherein a steering control signal is output to the steering actuator (206) that is weaker than a value.   The positioning device (199) is provided with a radio wave detection device (102) for detecting the strength of radio waves from the GPS antenna (200). When the radio wave detected by the radio wave detection device (102) is lower than a predetermined value, the steering actuator ( 2. The automatic steering device for a farm work vehicle according to claim 1, wherein a steering control signal is output to make the operation speed of 206) slower than a predetermined value and the traveling speed slower than a predetermined value.   An antenna frame (201) for mounting the GPS antenna (200) is provided above the work seat (41) of the traveling vehicle body (2), and a roof (110) is provided above the antenna frame (201). The automatic steering device for a farm work vehicle according to claim 3.

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