JPH07241505A - Controlling method for automatic travel type spray vehicle and the spray vehicle - Google Patents

Abstract

PURPOSE:To improve spray of spraying liquid onto a wall body in a corner part by traveling an automatic travel type spray vehicle while alternately repeating advance and stop during turning in a method for controlling the automatic travel type spray vehicle which travels along the wall body and turns in the corner part. CONSTITUTION:A turning travel means 60 alternately turns on and off a motor 66 in accordance with the elapse of time during turning. A right or left-side driving wheel of the outside in the turning direction becomes a driving state in a time for turning on the motor 66. An automatic travel type spray vehicle for disinfecting a barn is advanced. The right or left-side driving wheel of the outside in a time for turning off the motor 66. The spray vehicle for disinfecting the barn is stopped. The respective parts of the wall surface of a corner part are convergently sprayed with disinfectant liquid by stopping of the spray vehicle for disinfecting the barn. Therefore reduction of spray density is controlled because of turning travel in the corner part in spite of increase of distance from a nozzle to the wall surface and increase of an angle of inclination of spray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an automatic traveling type spraying vehicle for spraying a disinfectant solution on a wall while traveling along a wall in a livestock house, and to an automatic traveling type spraying vehicle.

[0002]

2. Description of the Related Art A self-propelled spraying vehicle that sprays a disinfectant solution on the wall of a livestock house sprays the disinfectant solution from the nozzles while traveling along the wall, and turns when it reaches the corner of the wall. do it,
It is designed to pass through a corner.

In the conventional self-propelled sprayer, the disinfecting liquid is sprayed at the corners in the same manner as at the non-corner, and there is no particular change.

[0004]

Since the orientation of the nozzle is set in conformity with the straight traveling of the automatic traveling type spraying vehicle in the non-corner portion, the orientation of the nozzle becomes unsuitable in the corner portion. Since the disinfectant solution hits the wall surface of the corner greatly deviates from the direction at right angles to the wall surface, and the corner is defined by the wall surface at almost right angles, the swirl is caused by curved lines such as arcs. Since the distance from the nozzle to the wall surface is increased by being performed along the traveling locus, the dispersal density and the collision speed of the disinfectant solution on the corner wall surface are reduced.

It is an object of the present invention to provide a method of controlling an automatic traveling type spraying vehicle and an automatic traveling type spreading vehicle capable of improving the spraying of the spraying liquid on the wall at the corners.

[0006]

The present invention will be described using reference numerals in the drawings corresponding to the embodiments. In the control method of the automatic traveling type spray vehicle (10) which is the premise of claim 1, the spraying liquid is sprayed from the nozzles (28) toward the side wall body while traveling along the wall body, At the corners of the corner, the vehicle turns and passes through the corners. Then, in the control method for the automatic traveling type spraying vehicle (10) according to the first aspect, the vehicle travels while alternately repeating traveling and stopping during turning.

[0007] The automatic traveling type spreading vehicle (1
In the control method of (0), while spraying the spray liquid from the nozzle (28) toward the side wall body, the non-corner portion of the wall body travels along the wall body, and the corner portion of the wall body, It makes a turn and passes through a corner. Further, in the control method of the automatic traveling type spray vehicle (10) of the second aspect, the injection pressure from the nozzle (28) is increased during turning, as compared with during non-turning.

An automatic traveling type spreading vehicle (1
In the control method of (0), while spraying the spray liquid from the nozzle (28) toward the side wall body, the non-corner portion of the wall body travels along the wall body, and the corner portion of the wall body, It makes a turn and passes through a corner. Then, in the control method of the automatic traveling spraying vehicle (10) according to the third aspect, the traveling speed is reduced during turning as compared to during non-turning.

According to a fourth aspect of the present invention, there is provided a method of controlling an automatic traveling type spreading vehicle (10) according to the first aspect of the present invention, further comprising: 28)
Increase the injection pressure from.

According to a fifth aspect of the present invention, there is provided a method of controlling an automatic traveling type spreading vehicle (10) according to the first, second, or fourth aspect of the present invention. Than,
Reduce running speed.

A self-propelled spraying vehicle (10) according to a sixth aspect of the invention has the following components (a) to (c). (A) Nozzle (2) that sprays spray liquid toward the side wall
8) (b) Corner detection means (40) for detecting the corner of the wall (c) (c) Turning means (60) for turning while alternately repeating running and stopping at the corner

An automatic traveling type spray vehicle (10) according to a seventh aspect of the invention has the following components (a) to (d). (A) Nozzle (2) that sprays spray liquid toward the side wall
8) (b) Corner detection means (40) for detecting the corner of the wall body (c) Turning travel means (60) for turning travel at the corner (d) When the nozzle (28) is turned during turning Injection pressure control means for increasing injection pressure (82)

An automatic traveling type spreading vehicle (10) according to claim 8 has the following components (a) to (d). (A) Nozzle (2) that sprays spray liquid toward the side wall
8) (b) Corner detecting means (40) for detecting the corner of the wall (40) (c) Swing traveling means (60) for turning traveling at the corner (d) Lowering the traveling speed during non-turning during turning Traveling speed control means (70)

An automatic traveling spraying vehicle (10) according to claim 9 is the automatic traveling spraying vehicle (10) according to claim 6, wherein the injection pressure of the nozzle (28) is further increased during turning, compared to during non-turning. It has an injection pressure control means (82).

An automatic traveling spraying vehicle (10) according to claim 10 is the automatic traveling spraying vehicle (10) according to any one of claims 6, 7 or 9, wherein the traveling speed is further reduced during turning while compared to during non-turning. It has a speed control means (70).

[0016]

According to the present invention, the automatic traveling type spreading vehicle (10) according to claims 1, 2, 3 and 4
In the control method of the
(28) Travel along the wall while spraying the spray liquid toward the wall. The self-propelled spray vehicle (10) turns at the corner and passes through the corner.

In the control method for the automatic traveling type spreading vehicle (10) according to the first aspect, at the corner portion, the automatic traveling type spreading vehicle (10) alternately repeats advance and stop. At the corners, the nozzle (28) caused by the traveling locus of a curved line such as an arc of the self-propelled spreading vehicle (10)
The distance from the wall to the wall increases, and the deviation of the contact of the spray liquid with respect to the surface of the wall from the right angle increases, so the spray density of the spray liquid decreases, but an automatic traveling spray vehicle during turning. As a result of the temporary stop of the progress of (10), the spray liquid from the nozzle (28) is concentrated and hits the same part of the wall body, and the decrease of the spray density is suppressed.

In the control method for the automatic traveling type dispersion vehicle (10) according to claims 2 and 4, the injection pressure from the nozzle (28) increases at the corners. At the corners, due to the increase in the distance from the nozzle (28) to the wall due to the traveling locus of the curved line such as the arc shape of the self-propelled sprayer (10), and the contact of the spray liquid with the surface of the wall. Since the deviation from the right angle increases, the spraying density of the spraying liquid decreases, but as a result of the increase of the injection pressure, the reaching distance of the spraying liquid increases and the collision pressure of the spraying liquid on the wall increases. As a result, it is possible to suppress a decrease in the dispersion density.

In the control method of the automatic traveling type spreading vehicle (10) according to claims 3 and 5, at the corners, the automatic traveling type spreading vehicle (10) is
Reduce running speed. In the corner, the self-propelled sprayer (1
Due to the increase in the distance from the nozzle (28) to the wall due to the running trajectory of the curved line of (0), etc., and the deviation of the spray liquid hitting the surface of the wall from the right angle direction increases. , The spraying density of the spraying liquid is reduced, but as a result of the decrease in running speed,
Since the influence of the deflection due to the turning speed component of the spray wheel (10) on the direction of the spray velocity component of the spray liquid from the nozzle (28) can be kept small, each part of the corner wall body,
The time for which the spray liquid is applied is increased, which suppresses the decrease in the spray density.

A self-propelled spraying vehicle (10) according to claims 6, 7 and 8.
Then, the self-propelled sprayer (10) is
8) Spray the spray liquid toward the wall. At the corner portion, the turning traveling means (60) causes the automatic traveling type spreading vehicle (10) to turn.

In the automatic traveling type spraying vehicle (10) of the present invention, the turning traveling means (60) alternately repeats advance and stop during turning of the automatic traveling type spreading vehicle (10).

In the automatic traveling spraying vehicle (10) according to claims 7 and 9, the injection pressure control means (82) increases the spraying pressure of the sprayed liquid from the nozzle (28) during turning, compared to during non-turning.

In the automatic traveling type spray vehicle (10) of the present invention, the traveling speed control means (70) lowers the traveling speed of the automatic traveling type spray vehicle (10) during turning, compared to during non-turning.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. 6 and 7 are a front view and a side view of the automatic traveling type spraying vehicle 10 for disinfecting a livestock house. This self-propelled spraying vehicle 10 for disinfecting livestock stalls inside the livestock stall along the wall to the left. The main body 12 is supported at the lower part by a front wheel 14 at the center of the front end in the left-right direction, and left and right left drive wheels 16 and right drive wheels 18 at the rear end. The main body 12 accommodates a motor 66 described later, elements for various controls, a battery, and the like. The front wheel 14 is a free wheel and changes its direction to an arbitrary direction according to an external force. The gate-shaped nozzle mounting pipe 20 has a gate-shaped upper portion 22 and a pair of lower portions 24 fixed to the front end of the main body 12 at the lower end and extending vertically on the left and right side portions of the main body 12, The upper part 22 and the lower part 24 are
The coupling ends are fitted to each other so that they can be separated from each other, and fixed by bolts 26. The plurality of nozzles 28 are arranged at appropriate intervals in a range extending from a predetermined height on the right side of the upper portion 22 to the upper end of the left side via the upper side.
Installed on. The nozzles 28 mounted on the right and left sides of the gate-shaped nozzle mounting pipe 20 are directed right and left, and the nozzles 28 mounted on the upper side of the gate-shaped nozzle mounting pipe 20 are directed directly upward. There is. The automatic traveling spraying vehicle 10 for disinfecting a livestock house circulates in the livestock house along the wall of the livestock house and sprays a disinfectant solution from each nozzle 28 onto the wall and the ceiling for disinfection.

FIG. 4 is a functional block diagram of driving mode switching control of the automatic traveling type spraying vehicle 10 for disinfecting livestock sheds. The front distance sensor 40 is attached to the front part of the main body 12 and detects the distance to an obstacle in front of the main body 12. Since the corner of the wall of the barn is demarcated by the two flat wall surfaces, the wall exists on the right side and in front of the automatic traveling type spraying vehicle 10 for barn disinfection at the corner. The arrival of the self-propelled spraying vehicle 10 at the corner can be detected by detecting a state in which it is sufficiently close to the front wall. The traveling mode switching means 42 detects, based on the detection signal from the front distance sensor 40, whether or not the wall stands in front of a sufficiently close front of the livestock disinfection automatic traveling sprayer 10, that is, whether or not the wall has reached a corner. To do. If the traveling mode switching means 42 is a non-corner part,
The straight traveling mode is set, and if it is a corner, the turning traveling mode is set. The automatic traveling sprayer 10 for disinfecting livestock is turning,
When there is no wall standing in front of you,
Since the distance to the front wall of the automatic traveling type spraying vehicle 10 for disinfection of livestock shed detected by the front distance sensor 40 becomes a predetermined value or more, the traveling mode switching means 42 detects that the vehicle has passed the corner and the livestock shed. The disinfection automatic traveling type spray vehicle 10 is returned from the turning traveling mode to the straight traveling mode.

FIG. 5 is a functional block diagram of the straight traveling mode control of the automatic traveling type spraying vehicle 10 for disinfecting livestock sheds. The lateral distance sensor 44 is attached to the right side portion of the main body 12 and detects the distance to the right wall. In determining the mounting position, the dimensions of the spray vehicle 10, the turning mechanism, the traveling speed, etc. are taken into consideration. Left electromagnetic clutch 48 and right electromagnetic clutch 50
Is the left drive wheel 16 and the right drive wheel from the motor 66 (FIG. 1)
It intervenes in each power transmission path up to 18, disconnects and connects the power transmission, and switches between driving and stopping of the left drive wheel 16 and the right drive wheel 18. The straight traveling means 46 detects the distance to the right wall by the detection signal from the lateral distance sensor 44, and when the distance increases to a predetermined value or more, that is, when it is too far from the wall, the left electromagnetic clutch 48 and The right electromagnetic clutch 50 is respectively engaged and disengaged, whereby the rotational power of the motor 66 is transmitted only to the left driving wheel 16, and due to the difference in rotation between the left and right, the automatic traveling type spraying vehicle 10 for disinfecting livestock stalls on the wall. Steered towards. Further, the straight traveling means 46, when the distance is reduced to a predetermined value or less, that is, when it approaches the wall too much, disconnects and contacts the left electromagnetic clutch 48 and the right electromagnetic clutch 50, respectively. The rotary power of the motor 66 is transmitted to the automatic traveling type spraying vehicle 10 for disinfection of the livestock house, which is steered in the direction opposite to the wall due to the difference in rotation between the left and right. In this way, the automatic traveling type spraying vehicle 10 for disinfecting livestock sheds is designed to drive straight, while only one of the left drive wheel 16 and the right drive wheel 18 is driven, and the left and right swings are alternately repeated. . Since the traveling speed of the automatic traveling spraying vehicle 10 for disinfecting livestock is about 50 cm / sec, it is possible to appropriately disperse the disinfectant liquid while exhibiting sufficient straight running performance for the progress with alternating runout to the left and right. And the steering structure can be extremely simplified.

FIG. 1 is a functional block diagram of straight traveling mode control. Left electromagnetic brake 62 and right electromagnetic brake 64
Respectively brake the left drive wheel 16 and the right drive wheel 18.
Since this automatic traveling-type spraying vehicle 10 for disinfecting livestock stalls in a counterclockwise direction, each corner passes by turning left. The turning traveling means 60 disconnects and engages the left electromagnetic clutch 48 and the right electromagnetic clutch 50, and turns on the left electromagnetic brake 62 and the right electromagnetic brake 64, respectively.
Turn off. As a result, a self-propelled spraying vehicle for disinfection of livestock houses 10
While the left drive wheel 16 is being braked, the rotational power is transmitted only to the right drive wheel 18, the left-right rotational difference is larger than in the straight traveling mode, and the vehicle can turn sharply. Depending on the situation, clockwise rotation may be required, and in such a right turn, the turning traveling means 60 connects and disconnects the left electromagnetic clutch 48 and the right electromagnetic clutch 50, respectively, and
The left electromagnetic brake 62 and the right electromagnetic brake 64 are turned off and on, respectively. The turning traveling means 60 also
The motor 66 is alternately turned on and off over time. For example, the on time and the off time of the motor 66, that is, the advancing time and the stopping time are 0.7 seconds and 1.0 seconds, respectively. When the motor 66 is on, the left drive wheel 16 or the right drive wheel 18 on the outer side in the turning direction is in a drive state, and the livestock disinfection automatic traveling sprayer 10 advances, whereas when the motor 66 is off, the turning is performed. Left drive wheel 16 or right drive wheel 18 on the outside in the direction
Despite being in contact with the left-hand side electromagnetic clutch 48 or the right-hand side electromagnetic clutch 50, the driving state is stopped, and the livestock disinfection automatic traveling spraying vehicle 10 is stopped. At each part of the wall surface of the corner, disinfectant solution is concentrated by stopping the automatic traveling spraying vehicle 10 for disinfecting livestock houses
Since it is sprayed, the nozzle 28
Despite the increase in the distance from the wall surface to the wall surface and the increase in the inclination angle of the spray of the disinfectant solution onto the wall surface, the decrease in the spray density is suppressed.

FIG. 2 is a functional block diagram of the traveling speed control of the automatic traveling type spraying vehicle 10 for disinfecting livestock houses. Travel speed control means
In the turning traveling mode, 70 lowers the rotation speed of the motor 66 as compared with the straight traveling mode. As a result, the traveling speed of the automatic traveling spraying vehicle 10 for disinfecting livestock at the corners is reduced, and each portion of the wall surface of the corners increases the time during which the spray liquid can be sprayed. Therefore, despite the increase in the distance from the nozzle 28 to the wall surface and the increase in the angle of inclination of spraying the disinfectant solution onto the wall surface, the decrease in the spray density is suppressed.

FIG. 3 is a functional block diagram of the injection pressure control. The injection pressure control means 82 switches the discharge pressure of the motor-driven pump 80, for example, by switching pressure control valves having different pressure control values, and sends the disinfecting liquid from the pump 80 to the upper portion 22. The pump 80 increases the injection pressure in the turning traveling mode as compared with the straight traveling mode. The injection pressure of the nozzle 28 is, for example, 1.5 kgf / square cm in the straight traveling mode.
On the other hand, in turning mode, 3.0 kgf / square c
m. As a result, the injection pressure from the nozzle 28 at the corner portion increases, and each portion of the wall surface of the corner portion can be sprayed with the spray liquid having the increased reach distance and collision pressure.
Due to the turning motion of the corner portion, a decrease in the spraying density is suppressed despite an increase in the distance from the nozzle 28 to the wall surface and an increase in the angle of inclination of spraying the disinfectant solution onto the wall surface.

The automatic traveling spraying vehicle 10 for disinfecting livestock in the embodiment is for disinfecting a livestock house. In the present invention, the spraying liquid is automatically traveled along the wall including the corners and the spray liquid is applied to the wall. It is applicable to the control method of all spraying automatic traveling vehicles and the automatic traveling vehicle. Furthermore, although the automatic traveling type spraying vehicle 10 for disinfecting livestock is a trackless type and an airless type spraying vehicle, the present invention is, for example, a system in which an unmanned operation is performed along a track designed to meander in a field or speed. It can also be applied to an aerial spraying automatic traveling type spraying vehicle such as a sprayer. In the case of the track type, in addition to the front distance sensor 40, it is possible to detect a corner by detecting a change from a straight track to a curved track, or detecting a lateral acceleration.

[0031]

According to the first and sixth aspects of the invention, the automatic traveling spraying vehicle is appropriately stopped during turning at the corner, so that the spraying amount of the spraying liquid on the wall of the corner is increased and the spraying is performed. The decrease in density can be suppressed.

In the inventions of claims 2, 4, 7 and 9, during spraying at the corners, the injection pressure at the nozzles increases, and as a result, the distance traveled by the spray liquid and the collision pressure on the wall increase, and the spray density is increased. Can be suppressed.

In the inventions of claims 3, 5, 8 and 10, the traveling speed of the self-propelled spraying vehicle decreases during turning at the corners, and as a result, each part of the wall of the corners is exposed to the spray liquid for a long time. As a result, it is possible to suppress a decrease in the dispersion density.

[Brief description of drawings]

FIG. 1 is a functional block diagram of straight traveling mode control.

FIG. 2 is a functional block diagram of traveling speed control of an automatic traveling spraying vehicle for disinfecting livestock sheds.

FIG. 3 is a functional block diagram of injection pressure control.

FIG. 4 is a functional block diagram of driving mode switching control of an automatic traveling spraying vehicle for disinfecting livestock sheds.

FIG. 5 is a functional block diagram of a straight traveling mode control of an automatic traveling type spraying vehicle for disinfecting a livestock house.

FIG. 6 is a front view of an automatic traveling type spraying vehicle for disinfecting a livestock house.

FIG. 7 is a side view of an automatic traveling type spraying vehicle for disinfecting a livestock house.

[Explanation of symbols]

10 Autonomous traveling sprayer for disinfection of livestock sheds (automatic traveling sprayer) 28 Nozzle 40 Forward distance sensor (corner detection means) 60 Turning travel means 70 Travel speed control means 82 Injection pressure control means

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[Procedure amendment]

[Submission date] April 11, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction content]

FIG. 5 is a functional block diagram of the straight traveling mode control of the automatic traveling type spraying vehicle 10 for disinfecting livestock sheds. The lateral distance sensor 44 is attached to the right side portion of the main body 12 and detects the distance to the right wall. In determining the mounting position, the dimensions of the spray vehicle 10, the turning mechanism, the traveling speed, etc. are taken into consideration. Left electromagnetic clutch 48 and right electromagnetic clutch 50
Is the left drive wheel 16 and the right drive wheel from the motor 66 (FIG. 1)
It intervenes in each power transmission path up to 18, disconnects and connects the power transmission, and switches between driving and stopping of the left drive wheel 16 and the right drive wheel 18. The straight traveling means 46 detects the distance to the right wall by the detection signal from the lateral distance sensor 44, and when the distance increases to a predetermined value or more, that is, when it is too far from the wall, the left electromagnetic clutch 48 and The right electromagnetic clutch 50 is respectively engaged and disengaged, whereby the rotational power of the motor 66 is transmitted only to the left driving wheel 16, and due to the difference in rotation between the left and right, the automatic traveling type spraying vehicle 10 for disinfecting livestock stalls on the wall. Steered towards. Further, the straight traveling means 46, when the distance is reduced to a predetermined value or less, that is, when it approaches the wall too much, disconnects and contacts the left electromagnetic clutch 48 and the right electromagnetic clutch 50, respectively. The rotary power of the motor 66 is transmitted to the automatic traveling type spraying vehicle 10 for disinfection of the livestock house, which is steered in the direction opposite to the wall due to the difference in rotation between the left and right. In this way, the automatic traveling type spraying vehicle 10 for disinfecting livestock sheds is designed to drive straight, while only one of the left drive wheel 16 and the right drive wheel 18 is driven, and the left and right swings are alternately repeated. . Since the traveling speed of the automatic traveling-type spraying vehicle 10 for disinfecting livestock is about 50 cm / sec, it is possible to show sufficient straight-line traveling performance for traveling with alternating runout to the left and right.
One can achieve adequate spray of extinguishing venom, and may very easily the steering structure.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location G05D 1/02 N (72) Inventor Manzo Matsuo 2-230 Takatsudo-cho, Midori-ku, Chiba-shi, Chiba

Claims (10)

[Claims] 1. A nozzle (28) sprays a spray liquid toward a side wall and travels along the wall, and at a corner portion of the wall body, a swirl is performed to move the corner portion. A method for controlling an automatic traveling spraying vehicle (10) adapted to pass through a vehicle, wherein the traveling method is characterized by traveling while alternating between traveling and stopping while turning. 2. The non-corner portion of the wall body travels along the wall body while the spray liquid is sprayed from the nozzle (28) toward the side wall body, and at the corner portion of the wall body. , Make a turn,
A self-propelled spreading vehicle adapted to pass through the corners.
In the control method of (10), the injection pressure from the nozzle (28) is increased during turning, as compared with during non-turning, the method for controlling an automatic traveling spraying vehicle. 3. The non-corner portion of the wall body travels along the wall body while the spray liquid is sprayed from the nozzle (28) toward the side wall body, and at the corner portion of the wall body. , Make a turn,
A self-propelled spreading vehicle adapted to pass through the corners.
In the control method of (10), the traveling speed is reduced during turning as compared to during non-turning. 4. The nozzle (2
8. The injection pressure from 8) is increased.
A method for controlling the self-propelled spreading vehicle described. 5. The method of controlling an automatic traveling spraying vehicle according to claim 1, wherein the traveling speed is reduced during turning as compared with during non-turning. 6. A nozzle (28) for ejecting a spray liquid toward a side wall (a), (b) a corner detecting means (40) for detecting a corner of the wall, and (c). An automatic traveling type spraying vehicle characterized by having a turning traveling means (60) for turning while alternately repeating running and stopping at a corner portion. 7. (a) a nozzle (28) for injecting a spray liquid toward a side wall, (b) a corner detecting means (40) for detecting a corner of the wall, and (c) a corner. The section is characterized by having a turning traveling means (60) for making a turning movement, and (d) an injection pressure control means (82) for increasing the injection pressure of the nozzle (28) during turning, as compared to during non-turning. A self-propelled spraying vehicle. 8. (a) A nozzle (28) for injecting a spray liquid toward a lateral wall body, (b) a corner detecting means (40) for detecting a corner portion of the wall body, and (c) corner. The section has an automatic traveling type spraying means (60) for rotating and traveling, and (d) traveling speed control means (70) for lowering the traveling speed during non-turning than during non-turning. car. 9. The self-propelled spraying vehicle according to claim 6, further comprising injection pressure control means (82) for increasing the injection pressure of the nozzle (28) during turning, compared to during non-turning. . 10. The automatic traveling type spraying vehicle according to claim 6, further comprising a traveling speed control means (70) for lowering the traveling speed during turning, compared to during non-turning.