JP2612389B2 - Body direction detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the direction of a vehicle body of a working vehicle provided with direction detecting means for detecting a traveling direction as an angle with respect to a reference direction.

[0002]

2. Description of the Related Art In the vehicle body direction detecting device, a direction sensor using geomagnetism has been used as a direction detecting means. However, the azimuth sensor using the terrestrial magnetism has a disadvantage that an error is easily generated in a detection value due to an influence of a surrounding high voltage line or an electromagnetic valve. Therefore, it was considered to use a laser gyro type direction sensor as a direction sensor instead of this.

[0003] When detecting the azimuth, it is necessary to set a reference azimuth as a reference for the detection. The setting of the reference azimuth is performed by setting the traveling direction of the work vehicle to a target traveling direction, for example, a lawn mowing work before starting traveling. In the case of a car, this is performed by initializing (for example, resetting) the detection value of the azimuth sensor in a state where the direction matches the direction of the work process.

[0004]

However, the laser gyro-type azimuth sensor has a drift characteristic in which the detected position value fluctuates with time. Therefore, errors accumulate with the passage of time. There is a problem that the reference direction initially set before the start of traveling shifts with time. Therefore, even when the vehicle body direction detecting device is applied to steering control of a work vehicle, there is a problem that the control cannot be performed satisfactorily.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to effectively prevent a deviation of a reference direction of the direction detecting means during traveling of a work vehicle, thereby always detecting an accurate direction. Is to make it possible.

[0006]

The feature of the vehicle body direction detecting device according to the present invention is that a plurality of beam light sources are provided on the ground side.
At predetermined intervals and arranged in a straight line, the beam light sources are configured to project the beam light in a state of scanning in the horizontal direction while maintaining the parallel state of the beam light to be projected, In the work vehicle, the plurality of light detectors as many as the plurality of beam light sources are installed at the same installation interval as the installation intervals of the plurality of beam light sources, and when the traveling direction matches the reference direction, It is provided in a state of receiving light beams from a plurality of beam light sources simultaneously,
The azimuth detecting means is configured to set a time when the plurality of photodetectors simultaneously receive the light beams as the reference azimuth.

[0007]

According to the characteristic structure of the present invention, a plurality of beam light sources on the ground side and a plurality of photodetectors on the work vehicle are provided at the same installation interval and in the same number, and the traveling direction of the work vehicle is detected in the direction. The parallel light beams projected from the beam light source when they coincide with the reference azimuth of the means are simultaneously received by the photodetector, and the azimuth detecting means can set the detected azimuth at that time as the reference azimuth. Therefore, the reference azimuth has a fixed angle relationship with the direction of the installation direction of the beam light source, and the installation direction of the beam light source is fixed to a fixed direction on the ground side. Is always set in a fixed direction. After the reference azimuth is set, the traveling direction of the moving vehicle is detected based on the reference azimuth.

[0008]

As described above, even when the reference direction of the direction detecting means is deviated while the work vehicle is running, the direction is accurately corrected to a constant value, thereby enabling accurate direction detection. Even when applied to steering control, the control can be performed well.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the embodiment of the present invention is applied to steering control of a lawn mower will be described below with reference to the drawings.

As shown in FIGS. 2 and 3, a single front wheel 1F steered by an electric motor M1 is attached to a front portion of a vehicle body V of a work vehicle C, and a pair of right and left wheels is mounted to a rear portion of the vehicle body V. Are mounted on the rear wheels 1L, 1R. At a substantially central lower portion of the vehicle body V, a rotary blade 2 for mowing, which is driven to rotate by the engine E, is mounted.
Although not described in detail, the engine E is also used as a drive source for the pair of left and right driven rear wheels 1L and 1R. Further, a transmission is not provided, and only forward / backward switching and stop operation can be switched.

At the front of the vehicle body V, three turf presence / absence detection sensors S1, S2, S3 for steering the front wheel 1F based on the presence or absence of uncut turf are arranged in the vehicle width direction. Installed in state. However, the sensors S1 and S3 at the left and right ends are located behind the front wheel 1F, and the sensor S2 at the center is located ahead of the front wheel 1F.

The turf presence detecting sensors S1, S2, S3
In addition, it is a so-called photo-interrupter type, and the light transmitted between the light source and the light receiving device which are arranged facing each other at an interval in the left-right direction is blocked by the uncut grass. Whether the sensor is attached to the uncut area A or the already-cut area B
That is, it is possible to determine whether it is. However,
Since the detection signals of the turf presence / absence detection sensors S1, S2, and S3 are intermittent depending on the density of the turf, for example, by performing processing such as integrating the detection signal,
This is converted into binary information indicating only one of the uncut area A and the already-cut area B.

The three sensors arranged in the vehicle width direction are the boundary L between the uncut area A and the already-cut area B (FIG. 1).
In order to make the vehicle travel automatically along the vehicle body,
When the vehicle is automatically driven, it is determined whether or not the end of the work process has been reached so that the vehicle can automatically turn to the next work process.

In addition, as shown in FIG. 1, the above-described lawn mowing work vehicle C has an uncut area A surrounded by a cut area B, and has an uncut area A. Mown land B
Along the boundary L from the one end of the work site to the other end, and as it reaches the end portion, turns to the uncut side and reverses the next work step adjacent thereto. That is, the so-called reciprocating travel is performed so that lawn mowing work in a predetermined range is automatically performed.

During the traveling of each work process, the three turf presence / absence detection sensors S1, S2,
When the sensor located on the cut side of S3 detects the uncut land A, it steers to the cut side and the sensor S2 at the center.
When the vehicle has detected the cut area B, the vehicle is steered to the uncut side so that the three steering control sensors S arranged in the vehicle width direction are arranged.
1, one of the ends of S1, S2, and S3 located on the side of the mowed land
A state in which only one sensor has detected the cut area B, and the other two sensors have detected the uncut area A, that is,
The vehicle V automatically travels while maintaining a state in which the vehicle body V is along the boundary L between the uncut area A and the already-cut area B as appropriate.

When the vehicle travels from one end of the working range to the other end along the boundary L between the uncut area A and the already-cut area B, when the end of the working area is reached, the surrounding area becomes the cut area B. The three turf presence / absence detection sensors S1, S
2 and S3 all detect the cut area B. Therefore, when all of the three turf presence / absence detection sensors S1, S2, and S3 detect the cut ground B, it is determined that the end of one work process has been reached, and the process moves to the next adjacent work process. It is made to turn to the uncut ground side at first.

As shown in FIG. 1, on the ground side, two beam light sources F1 and F2 are provided at a predetermined installation interval in a traveling direction at the start of traveling of the work vehicle C, that is, in a direction of a first work process. D. Then, the two beam light beams G1 and G2 projected from the two beam light sources F1 and F2 respectively are scanned at the same height from the ground and in the horizontal direction while maintaining a parallel state with each other. It is configured. Although not described in detail, the beam light sources F1 and F2 are composed of a laser light emitting device, a scanning mirror, and the like.

On the other hand, as shown in FIGS. 1 to 3, the work vehicle C is provided with a work body corresponding to the two beam light sources F1 and F2 on the ground side, respectively, on the front side and the rear side of the vehicle body V. Car C
In the traveling direction, two light receiving sensors S4 and S5 as photodetectors are installed at the same installation interval D as the installation interval D of the two beam light sources F1 and F2. 2 above
Each of the light receiving units of the light receiving sensors S4 and S5 has the same height as the height of the two beam light sources F1 and F2 from the ground, and the light receiving units are directed leftward in the traveling direction. Have been. Therefore, only when the traveling direction of the work vehicle C matches the direction of the installation direction of the two beam light sources F1 and F2, the two beam lights G1 and G2 are converted to the two light receiving sensors S4 and S5. Are received at the same time.

Further, the work vehicle C is provided with a laser gyro type azimuth sensor S6 as azimuth detecting means for detecting the traveling direction of the work vehicle C. The two light beams G1 and G2 are used as the two light receiving sensors. When the light is received simultaneously by S4 and S5, the reference azimuth K of the azimuth sensor S6 is set. Therefore, the direction of the installation direction of the two beam light sources F1 and F2 corresponds to the reference direction K. During traveling, the traveling direction of the work vehicle C is detected as an angle with respect to the reference azimuth K, and the steering amount is determined according to the detected value, that is, the deviation of the traveling direction with respect to the reference azimuth K.

Next, a control configuration for automatically moving the work vehicle C based on the information of the sensors S1 to S6 will be described. As shown in FIG. 4, the steering control is performed by controlling the operation of the steering electric motor M1 based on the detection information of the three grass presence / absence detection sensors S1, S2, S3 and the direction sensor S6. And the two light receiving sensors S
4, S5 sets the reference direction K of the direction sensor S6 based on the detection information when the two light beams G1 and G2 are simultaneously received, and furthermore, the three turf presence / absence detection sensors S1 and S2. , S3, a control device 3 using a microcomputer is provided to determine whether or not the end of the work process has been reached.

Next, based on the flowchart shown in FIG. 5, the three turf presence / absence detection sensors S1, S2, S3,
The direction sensor S6 and the two light receiving sensors S
The steering control executed based on the detection information of S4 and S5 will be described. However, when traveling between work strokes, the information of the turf presence / absence detection sensor located at the uncut side end is not used, and the center turf presence / absence detection sensor S2 and the turf presence / absence detection sensor located at the already cut side are not used. The deviation direction of the uncut grass A and the already-cut grass B relative to the boundary L is determined based on the information of the two sensors. Then, the steering operation amount and the steering direction are set based on the information of the direction sensor S6. However, in the following description, it is assumed that the vehicle travels in a state where the boundary L is located on the left side of the vehicle body (see FIG. 1).

First, before starting traveling, the work vehicle C is turned to the direction of the first work process and the two light receiving sensors S4 and S5 are turned on.
Receive the two light beams G1 and G2 at the same time, and initialize the reference direction K of the direction sensor S6. Specifically, the detection direction θk of the direction sensor S6 is reset. When the vehicle starts traveling, whether or not the sensor S2 for detecting the presence or absence of turf at the center detects ON (there is turf) is OFF.
It is determined whether or not (without grass) is detected. If it is ON, it is determined that there is no shift in the cutting direction, and the sensor S1 located on the boundary side detects ON (with grass). It is determined whether or not an off-cut (no grass) is detected. If it is off, it is determined that there is no shift to the uncut side, that is, it is shifted to both the uncut side and the already cut side. The target azimuth θ of the steering operation is set to the reference azimuth K.

After the start of traveling, the central sensor S2 is
If the absence of grass is detected by FF, it is determined that the target azimuth is shifted to the cut side, and the target azimuth θ is set to the reference azimuth K.
Is set to a value obtained by subtracting the set value α from. That is, the sign of the target azimuth θ is set to the minus side when turning to the uncut side. Similarly, when the central sensor S2 is ON and the boundary sensor S1 is ON, it is determined that the target azimuth is shifted to the uncut side, and the target azimuth θ is set to the reference azimuth K by the set value α. Set to the added value.

After setting the target azimuth θ, a deviation Δθ between the target azimuth θ and the detected azimuth θk of the azimuth sensor S6 is obtained, and the obtained deviation Δθ is multiplied by a control gain G to obtain a steering angle θst to be operated. And the steering operation of the front wheel 1F is performed. The sensor may detect whether or not the front wheel 1F has reached the steering angle θst, but the sensor is omitted by setting the steering angle θst as the drive time of the steering electric motor M1. Is also good.

Next, it is determined whether or not the end of the work process has been reached based on whether or not all of the three turf presence / absence detection sensors S1, S2, S3 detect the cut ground B. If the end has not been reached, the flow returns to the flow of judging the simultaneous light receiving state of the two light receiving sensors S4 and S5. If the simultaneous light receiving state, the reference direction K of the direction sensor S6 is set. If it has reached the end, operate the front wheel 1F to the set angle and move
It is turned so as to change its direction by 80 degrees and is moved to the start end of the next operation step. Then, when it is detected that the direction of the vehicle body V has been inverted by 180 degrees from the direction at the start of turning based on the detection information of the direction sensor S6, the turning operation for changing the direction is ended.

[Alternative Embodiment] In the above embodiment, the installation directions of the two light receiving sensors S4 and S5 on the work vehicle C side and the two beam light sources F1 and F2 on the ground side are changed in the direction of the work process of the work vehicle C. However, it is not always necessary to make them coincide with each other. For example, they may be set in a direction orthogonal to each other, or may be set in any other angle direction.

In the above embodiment, the height positions of the light receiving portions of the two light receiving sensors S4 and S5 on the front side and the rear side of the work vehicle C are the same. Alternatively, different heights may be used. In addition, it is necessary to change the heights of the two beam light sources F1 and F2 on the ground side accordingly. The number of the light receiving sensors and the beam light sources is not limited to two, and may be three or more.

Further, in the above embodiment, the light receiving portions of the two light receiving sensors S4 and S5 on the front side and the rear side of the work vehicle C are directed to the left side in the traveling direction of the work vehicle C. A part may be provided. Alternatively, the light receiving sensor may be rotated 180 ° after turning at the end of the work process. This has the advantage that the reference orientation of the orientation detection means S6 can be set in both directions of the work process.

In the above embodiment, the azimuth sensor S6 of the laser gyro type is used as the azimuth detecting means. Alternatively, an azimuth sensor utilizing geomagnetism may be used.

In the above-described embodiment, an example in which the present invention is applied to the working vehicle C having one steering front wheel 1F and a pair of left and right driving rear wheels 1L and 1R has been described. In addition, a pair of left and right front wheels and a pair of left and right rear wheels are provided so that each of the front and rear wheels functions as a drive wheel or a steering wheel, and the front and rear wheels are steered in phase. The present invention can also be applied to a work vehicle that can select one of three types of steering modes, namely, a parallel steering mode, a four-wheel steering mode in which steering is performed in opposite phases, and a two-wheel steering mode in which only the front wheels are steered.

Further, in the above-described embodiment, the case where the work vehicle C is driven fully automatically is illustrated. However, a form in which a person rides and artificially controls the vehicle, or a form in which the vehicle is remotely controlled by radio can be used together. You may do so.

Incidentally, reference numerals are written in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a work mode.

FIG. 2 is a schematic plan view of a working vehicle.

FIG. 3 is a side view of the same.

FIG. 4 is a block diagram of a control configuration.

FIG. 5 is a flowchart of a control operation.

[Explanation of symbols]

 C Work vehicle D Installation interval F1, F2 Beam light source G1, G2 Beam light K Reference direction S4, S5 Photodetector S6 Direction detection means

Claims (1)

(57) [Claims] 1. A vehicle body direction detecting device for a working vehicle (C) provided with a direction detecting means (S6) for detecting a traveling direction as an angle with respect to a reference direction (K), wherein a plurality of beam light sources ( F1, F2) are arranged in a straight line at a predetermined installation interval (D), and the beam light sources (F1, F2) are arranged in a horizontal direction while maintaining the parallel state of the beam lights projected from each other. It is configured to project light beams (G1, G2) in a scanning state, and the plurality of beam light sources (F1, F2) are provided to the work vehicle (C).
The same number of photodetectors (S4, S5) as in 2) are provided at the same installation interval (D) as the installation interval (D) of the plurality of beam light sources (F1, F2), and the traveling direction is the same. When coincident with the reference direction (K), the plurality of beam light sources (F
, F2), the azimuth detecting means (S6) is provided so as to simultaneously receive the light beams (G1, G2) from the plurality of photodetectors (S6).
4, S5) sets the time when the light beams (G1, G2) are simultaneously received as the reference azimuth (K).