JPH0365122B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic traveling work vehicle, and more specifically, to a predetermined range of work areas, the boundary detection results of scanning sensors A, A that detect boundaries between treated work areas and untreated work areas. Based on this, while detecting the boundaries, the vehicle automatically travels based on a travel order sequence for a plurality of predetermined travel journeys and a direction change sequence for moving to the next journey after completing one travel journey. The present invention relates to a self-driving work vehicle configured.

Conventionally, this type of self-driving work vehicle, for example, a ground work vehicle such as a lawnmowing work vehicle, has been equipped with this system to automatically perform ground work within a predetermined range of work area where the surrounding area has been treated as a work area in advance. Divide the work area into multiple travel routes corresponding to the work width in advance,
Control is performed to cause the vehicle to travel automatically while sequentially moving between the plurality of travel strokes.

The order sequence for traveling through each of the above travel strokes is a reciprocating style in which each travel stroke is set in parallel and the direction is changed 180 degrees in the next stroke, or There is a circular driving format in which the travel path is set in a direction that rotates the work area sequentially, and the next step is a 90 degree turn, but in any of the driving formats, each travel step Since the scanning steering control is performed based on the results of detecting the driving location, that is, the boundary of each stroke by the scanning sensor, there is relatively little deviation in the driving direction, but the direction change at the end of each stroke is generally set in advance. Because this was carried out using a fixed pattern control based on a sequence of There was an inconvenience that the work marks were uneven.

Therefore, in order to eliminate the above-mentioned inconvenience, the present applicant has proposed, in Japanese Patent Application No. 58-187345, etc., a method for correcting the direction of the vehicle body after a direction change and the position for the next stroke. An automatic traveling work vehicle has already been proposed that is equipped with a vehicle body position correction means that combines a steering wheel for turning operations and a steering wheel for parallel movement for position correction.

In the above means, the operation of moving the car body in parallel to correct the position for the next stroke has a very large effect, but when aligning the car body along the boundary of the next stroke, after detecting the end of the stroke, a large steering angle is required. If parallel steering is performed only when the boundary is detected, the object will overshoot after the boundary is detected, and the steering must be performed in the opposite direction.As a result, it takes time to align the boundary, and the work trace becomes uneven in the left and right direction. Not only does it look bad, but
This also affected the convergence of subsequent copy steering control, and on the other hand, when parallel steering was performed only at a small steering angle, a new inconvenience occurred in that it took time to detect the boundary.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to automatically change the orientation of the vehicle body and its position relative to the boundary after the direction change when repeatedly performing ground work while automatically changing direction. To control the condition so that it follows the boundary of the end of the stroke,
To provide an automatically traveling work vehicle equipped with a steering control means that leaves less uneven work marks when correcting its position.

In order to achieve the above object, an automatic driving work vehicle according to the present invention is configured such that both the front wheels and the rear wheels can be steered, and is equipped with an orientation sensor that detects the direction of the vehicle body, and is equipped with a direction sensor that detects the orientation of the vehicle body. When changing direction, after its initiation,
By the time the copying sensor detects the next stroke end, the steering is automatically operated to correct the orientation of the vehicle body so that the direction detected by the orientation sensor coincides with a preset reference orientation, and
After correcting the vehicle body direction, the front and rear wheels are set at a preset steering angle in the same direction in order to correct the lateral position of the vehicle body for the next stroke based on the detection result of the deviation with respect to the boundary of the next stroke by the copying sensor. If the vehicle body is not aligned with the boundary even after the steering operation is performed and the vehicle body is moved a preset distance, the steering angle is smaller than the predetermined steering angle until it is detected that the vehicle body is along the boundary. The vehicle is characterized in that it is provided with means for correcting the position in the left and right direction by performing a steering operation at a predetermined steering angle.

Because of the above characteristics, the following excellent effects have been achieved.

That is, in order to correct the lateral position of the vehicle body for the next stroke after a direction change, when performing parallel steering operation at a predetermined steering angle, it is performed in stages with two levels of operation amount, large and small. The position is corrected in two steps: quickly correcting the position, and if no boundary is detected while moving a predetermined distance, then making detailed position corrections with an emphasis on accuracy. As a result, it has become possible to quickly align the vehicle body with the next stroke boundary with a short overall travel distance and with few unevenness in the work trace.

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a lawn mowing device 4 is suspended between the front and rear wheels 2, 3 of a vehicle body 1 so as to be movable up and down, and an unmown area B and an already mowed area C, which are the boundaries of a working area A, are suspended.
Tracing sensors 5, 5, which will be described later, are provided on the front left and right sides of the vehicle body 1 to determine the demonic realm L of The lawn mowing vehicle is configured as a movable autonomous vehicle.

Further, the vehicle body 1 is provided with a fifth wheel 6A as a distance sensor 6 that generates a predetermined number of pulse signals per unit travel distance _l0 in order to continuously detect the travel distance l of the vehicle body 1, In order to detect the direction (azimuth) of the vehicle body 1, a geomagnetic sensor is provided as an azimuth sensor 7, which detects the azimuth by detecting changes in the strength of the earth's magnetic field.

The front wheels 2, 2 and the rear wheels 3, 3 are both configured to be able to be operated by steering.
By steering the front and rear wheels 2 and 3 in the same direction, the vehicle body 1 moves in parallel without changing its orientation, and at the same time, the front and rear wheels 2 and 3 are steered in relatively opposite directions. This allows it to turn with a very small turning radius.

The scanning sensor 5 includes two optical sensors S ₁ ,
The optical sensors S ₁ and _{S 2}
As shown in FIG. 2, U-shaped sensor frames 9 and 9 are attached to the vehicle body 1 at the distal ends of the support frame 8 whose base end is fixed to the lawn mower 4.
Light emitting elements P ₁ are arranged adjacent to each other in the left and right direction, and light emitting elements P 1 are respectively arranged on the inner facing surface of this sensor frame 9.
and a light-receiving element _P2 are provided as a pair, and by sensing the presence or absence of grass passing between the light-emitting element _P1 and the light-receiving element _P2 , it is possible to distinguish between an unmowed area B and a mown area C. It is configured as expected. Note that the copying sensor 5 is not limited to those using optical sensors S ₁ and S ₂ ;
It may be constructed from any type of sensor, whether contact type or non-contact type.

Each light receiving element of the optical sensors S ₁ and S ₂
The discrimination signal for unmowed area B and mown area C obtained from P ₂ and P ₂ becomes a discontinuous pulse-like signal because the grass passes intermittently. Therefore, in order to convert the signal into a continuous discrimination signal, the signal is configured to be inputted to the control device 10, which will be described later, after performing an integral process.

a programmable counter 11 that counts the number of output pulses of the distance sensor 6 and outputs a carry signal C ₂ for each preset count value in order to integrate the output signal C ₁ of the light receiving element P ₂ ;
A flip-flop 12 is provided which is reset by the carry signal _C2 of the counter 11, and the counter ₁₁ is reset by the output signal C1 of the light receiving element _P1 .
2, and this counter 1
1 and flip-flop 12 to form a digital filter 13, and unmoved area B and already cut area C
Continuous boundary L discrimination signal corresponding to each state
It is designed to obtain C ₀ .

The operation of this digital filter 13 will be briefly explained below.

The counter 11 is repeatedly reset by the output pulse signal _C1 of the light receiving element _P2 regardless of its count value, and the flip-flop 12 is set. Then, when the grass is gone, this pulse signal _C1 becomes "L" level, and
Only when the vehicle has traveled a predetermined distance _l0 and the counter 11 counts the output signal _C3 of the distance sensor 6 up to the count value corresponding to the predetermined distance _l0 ,
The counter 11 outputs a carry signal _C2 , and the flip-flop 12 is reset. Therefore, the output of the flip-flop 12 has a boundary determination function that continuously repeats the "H" level corresponding to the grass detection state, that is, the detection of unmowed land B, or the "L" level corresponding to the grassless state, that is, the detection of mowed land C. signal
C ₀ is obtained.

Hereinafter, a control system for controlling the travel of the lawn mowing vehicle based on the parameters detected by the tracing sensors 5, 5, distance sensor 6, and direction sensor 7 configured as described above will be described.

As shown in FIG. 3, the control system has signals from each of the sensors 5, 5, 6, and 7 inputted to a control device 10 whose main part is composed of a microcomputer. ,5,
Hydraulic cylinders 14 and 15 for steering operation of the front and rear wheels 2 and 3 are operated to automatically control the running direction and speed of the vehicle body 1 by calculating the detected parameters 6 and 7. electromagnetic valves 16, 17 and hydraulic continuously variable transmission 1
The control signal is configured to generate a control signal for driving each actuator such as a motor 19 for operating the gear shift position of 8.

In FIG. 3, R ₁ and R ₂ are potentiometers for detecting the actual steering angles of the front and rear wheels 2 and 3 and providing feedback to the control device 10.
_R3 is a potentiometer that similarly detects the shift position of the transmission 18.

Control for automatically changing direction will be explained below.

In addition, in order to mow the entire work area A, the direction change in this embodiment is basically to turn the outer periphery of the work area in a 90 degree direction from the outer periphery to the inner periphery, as shown in Fig. 4A. This is done by traveling each stroke sequentially while switching, and if the remaining number of strokes on the short side l _b of the work area A becomes less than the predetermined stroke N',
As shown in FIG. 4B, by changing direction by 180 degrees at the end of each stroke, the traveling style is changed so that the next stroke is sequentially reciprocated.

In any of the above travel formations, as shown in FIG. While traveling a predetermined distance l' until moving onto the mowed ground B, the front and rear wheels 2 and 3 are both steered in the same direction at a predetermined steering angle θ ₁ , and the scanning sensor 5 detects the next stroke. The position of the vehicle body 1 in the left-right direction for the next stroke is corrected so as to be along the boundary L between the unmowed land B and the mowed land C.

_{Furthermore ,} as shown in FIG. By performing the steering operation until the steering wheel runs along the boundary L, convergence with respect to the boundary L is improved with less unevenness of the work trace.

Incidentally, FIG. 6A and B show the control device 10 explained above.
This is a flowchart showing the operation of FIG.

In addition, in correcting the vehicle body position after the direction change,
Instead of correcting the position by parallel movement with a small steering angle θ ₂ , the position may be corrected by steering only the front wheels 2, 2 or only the rear wheels 3, 3.

Furthermore, as shown in FIG. 6C, when the vehicle body position is corrected by changing the part surrounded by the dotted line in the center of FIG. Based on the detection result of whether the deviation is toward the mowed land C or the mowed land C side, if the steering angle is toward the mowed land C, the steering angles θ ₁ and θ ₂ are changed to the unmoved land B side. A predetermined amount α from the case of deviation to
It is also possible to configure the steering operation to be performed by reducing the number of steps to prevent uncut mowing.

[Brief explanation of drawings]

The drawings show an embodiment of the automatic driving vehicle according to the present invention, in which FIG. 1 is an overall plan view of the lawn mowing vehicle, FIG. 2 is a front view of the main parts of the scanning sensor, and FIG. 3 is a block diagram of the control system. Figure 4 A and B are explanatory diagrams of lawn mowing work, Figures 5 A and B are explanatory diagrams of correcting the vehicle body position after changing direction, and Figure 6 A, B, and C are flowcharts showing the operation of the control device. It is. 1...Vehicle body, 2...Front wheel, 3...Rear wheel, 5...
Copying sensor, 7... Direction sensor, Ψ... Detection direction, Ψ ₀ ... Reference direction, B... Untreated work area,
C... Treated work area, L... Boundary, l'... Predetermined distance, θ ₁ , θ ₂ ... Predetermined steering angle, α... Predetermined amount.

Claims (1)

[Scope of Claims] 1. A method of detecting a boundary in a predetermined range of a working area based on the boundary detection results of scanning sensors 5, 5 that detect the boundary L between a treated working area C and an untreated working area B. However, it is an automatic driving work vehicle that is configured to run automatically based on a predetermined travel order sequence for multiple travel strokes and a direction change sequence for moving to the next stroke after completing one travel stroke. At that, front wheels 2, 2 and rear wheels 3, 3
A direction sensor 7 detects the orientation of the vehicle body 1.
is provided, and when changing direction based on the direction change sequence, after the start of the direction change sequence, the copying sensor 5,
By the time 5 detects the end of the next stroke, the steering operation is automatically performed to correct the direction of the vehicle body 1 so that the direction Ψ detected by the direction sensor 7 matches the reference direction Ψ ₀ set in advance. After the orientation of the vehicle body 1 has been corrected, the front and rear wheels 2 and 3 are moved in the same direction in order to correct the lateral position of the vehicle body 1 for the next stroke based on the detection result of the deviation with respect to the boundary L of the next stroke by the copying sensors 5 and 5. If the vehicle body 1 moves a predetermined distance l' by performing a steering operation at a predetermined steering angle θ ₁ , and even after moving the predetermined distance l', the vehicle body 1 does not follow the boundary L, the boundary The present invention is characterized by being provided with means for correcting the position in the left and right direction by performing a steering operation at a predetermined steering angle θ ₂ smaller than the predetermined steering angle θ ₁ until it is detected that the steering angle is along L. Self-driving work vehicle. 2 When the front wheels 2, 2 and the rear wheels 3, 3 are steered in the same direction at predetermined steering angles θ ₁ , θ ₂ , the direction of deviation of the vehicle body 1 with respect to the boundary L is toward the treated work area C side. The automatic traveling work vehicle according to claim 1, wherein the steering operation is performed at a steering angle that is smaller by a predetermined amount α than when the vehicle is on the untreated work site B side.