JP2896017B2 - Lawn mower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lawn mowing section for mowing a lawn with a set cutting width as the vehicle travels, and a boundary detection for judging a boundary between an unprocessed work place and a processed work place based on the presence or absence of a lawn. And a control means for executing steering control for operating a steering operation means so that the vehicle body travels along the boundary determined by the boundary detection means.

[0002]

2. Description of the Related Art A lawn mowing vehicle of this type is configured as a self-propelled work vehicle for performing lawn mowing work without human intervention. For example, a photo interrupt type sensor for detecting the presence or absence of lawn is provided. Is reciprocated along the vehicle body width direction by a rocking mechanism or the like, and the movement position of the sensor in the vehicle body width direction is detected by, for example, a potentiometer attached to a rocking shaft of the rocking mechanism, and the detection of the potentiometer is performed. At each moving position where the value (output voltage) becomes a plurality of preset values, the presence / absence of uncut grass is detected by the sensor. The intermediate position between the approached turfless detection position and the adjacent turfside detection position on the unprocessed work site side is determined as the boundary between the unprocessed work site and the processed work site. That. Note that the lawn mowing vehicle detects the difference between the proper position where the vehicle body should be positioned with respect to the determined boundary and the current position as a positional deviation in the lateral width direction, that is, the position of the boundary in the vehicle lateral width direction. A position deviation from the reference position of the vehicle body is obtained, and based on the position deviation information, the vehicle is steered so as to automatically maintain a proper position with respect to a boundary between the unprocessed work place and the processed work place. Controlled.

[0003] Conventionally, although not a lawn mowing vehicle, based on information obtained by detecting the presence or absence of a grain culm in a field by a boundary sensor directed to the traveling direction of the vehicle body, the uncultivated land and the already-mown land of the grain culm in the field are determined. (See, for example, JP-A-63-267204).

[0004]

By the way, for example, the cutting is performed in sequence at a set cutting width along a plurality of adjacent work steps in a work place, and the last remaining stroke width becomes smaller than the set cutting width. Under such conditions, the boundary is located on both the left and right sides of the vehicle body. In this case, in the above-described conventional boundary detecting device, a single sensor is provided on the vehicle body as a sensor for detecting the boundary (a grain stalk presence / absence detection sensor), and one boundary is determined based on the detection information of the sensor. Because
As described above, when the boundaries are located on the left and right sides of the vehicle body, the deviation between the position of one of the left and right boundaries and the reference position on the vehicle body side is determined. That is, when calculating the positional deviation in the vehicle body width direction, only one of the boundary information on the left and right sides of the vehicle is used, and the other boundary information is not used.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide a structure in which, when the remaining width of the turf is narrow and the boundaries are located on the left and right sides of the vehicle body, the boundaries on both the left and right sides are provided. On the other hand, the steering control is performed so that the vehicle body is positioned in a balanced manner, so that the narrow turf can be appropriately cut and run without leaving uncut.

[0006]

According to a characteristic feature of the lawn mowing vehicle according to the present invention, the boundary detecting means is configured to determine the boundary on each of the right and left sides of the vehicle body, and the control means includes: A left-right deviation between the position in the vehicle width direction of the boundary of each of the right and left sides of the vehicle body determined by the means and a reference position in the vehicle width direction of the vehicle body is obtained, and the magnitude of the left-right deviation is substantially the same. In this case, the steering control is executed.

[0007]

According to the characteristic structure of the present invention, the boundary between the unprocessed work place and the processed work place is determined based on the presence or absence of turf in each of the right and left sides of the vehicle body. The left and right deviation between the position in the lateral direction and the reference position in the lateral direction of the vehicle body is obtained, and the steering operation means is operated so that the magnitude of the lateral deviation becomes substantially the same, and the steering control is performed. Will be executed.

[0008]

Therefore, according to the characteristic structure of the present invention, since the steering position is controlled so that the position of the vehicle body in the lateral width direction is balanced with respect to both right and left boundaries, the width of the turf is small. In the case where the boundaries are located on the left and right sides of the vehicle body, the conventional boundary detection device only controls the steering of the vehicle body position with respect to only one of the left and right sides of the vehicle body. A lawn mowing vehicle that moves the car body in a well-balanced position with respect to both boundaries on both the left and right sides and cuts appropriately with no remaining mowing at the lawn mowing part that cuts with the set cutting width as the vehicle travels is obtained. Can be

[0009]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 4 to 6, a lawn mowing rotary blade body 2 is attached to a lower portion of a vehicle body V on which an engine E is mounted, and a steering idle front wheel 1F is mounted on front and rear portions of the vehicle body V. A pair of left and right driving rear wheels 1L, 1R to which the driving force of the engine E is transmitted via the case 3 is mounted to constitute a lawn mowing vehicle. Here, the rotary blade body 2 corresponds to a lawn mowing unit that mows the lawn with a set cutting width as the vehicle travels. The front wheel 1F includes a steering gear 1 for directly steering the front wheel 1F.
A, a steering motor M1 for automatic steering as a steering operation means, and a motor gear 1B for transmitting the driving force of the steering motor M1 to the steering gear 1A. An encoder 14 for detecting the number of rotations is provided on the rotation shaft of the front wheel 1F. A fluxgate type geomagnetic sensor S0 using a toroidal core is installed on the vehicle body V in order to detect the current azimuth when the work vehicle is traveling.

As shown in FIG. 2, on the front side of the vehicle body V,
Four turf height detection sensors S1, S2, S3, S4 consisting of reflection type photo interrupters for detecting the presence or absence of uncut grass
Are dispersedly arranged via a swinging mechanism 23 for swinging back and forth in the vehicle width direction of the vehicle body V, and the turf height detection sensors S1,
S2, S3, and S4 detect a turfed state where the turf is not cut if the turf height is large, and detect a turfless state where the turf is cut if the turf height is small. . Therefore,
The turf height detecting sensors S1, S2, S3, S4 constitute turf presence / absence detecting means 22 for detecting the presence or absence of turf.

The swing mechanism 23 has a bifurcated distal end arm 24 whose base end is pivotally attached to the front end of the vehicle body V so as to be rotatable about a vertical axis. The cam mechanism 25 is arranged so that the eccentric cam 25A contacts the auxiliary arm 24A attached to the base end of the arm 24. The turf height detection sensors S1 and S2 or the turf height detection sensors S3 and S4, which are arranged at a distance W in the vehicle width direction, are attached to the forked ends of the arm 24 via the mounting member 26. Installed. The mounting member 26 is provided with a turf height detection sensor S1, S2 or a turf height detection sensor S.
In order to adjust the ground height of S3 and S4, the vertical position is adjusted by a vertical adjustment mechanism provided in the middle thereof, and then the distal end portion 26B is fixed. With the above configuration, the eccentric cam 25A is connected to the sensor swing motor m
(See FIG. 1), the arm 24 swings in the vehicle width direction, and the pair of right and left turf height detection sensors S1, S2 or turf height detection sensors S3, S4 respectively move in the vehicle width direction. Is scanned back and forth.

Therefore, the presence or absence of a turf at a predetermined ground height is determined by the turf height detection sensors S1 and S2 or the turf height detection sensors S3 and S4 which are moved and scanned by the rocking mechanism 23 as described later. (See FIG. 9) the distance W
Is detected at four detection intervals, whereby eight turf presence / absence data D0 to D7 or D8 to D15 are obtained by the swing scanning of the pair of sensors S1, S2 or S3, S4. Each of the data D0 to D15 is digital data indicating "1" when there is grass and "0" when there is no grass. The detection interval is determined by detecting a moving position by a potentiometer G provided on a rotation shaft of the eccentric cam 25A. As described above, the oscillating mechanism 23 constitutes the operating means 23 for repeatedly reciprocating the turf presence / absence detection means 22 along the vehicle width direction, and the potentiometer G controls the turf presence / absence detection means 22 Position detecting means G for detecting the moving position in the lateral width direction is configured.

The mounting member 26 is pivotally supported by the arm 24 so as to be able to swing back and forth with respect to the traveling direction with its upper base end as a fulcrum. A projection 28A is provided between the projection 26A and the tip of the arm 24. A spring 28 is provided between the projection 26A and the distal end of the arm 24 for urging the mounting member 26 forward. An adjusting screw 29 for adjusting the angle is screwed and supported by the projecting portion 26A in a state where the tip of the adjusting screw 29 abuts against the arm 24 by the urging force of the spring 28. Thereby, the turf height detection sensor S1,
When S2 or the turf height detection sensors S3 and S4 hit a foreign object or the like, the turf height detection sensor is prevented from breaking as much as possible by falling backward, and the turf that the rearward fall hits the foreign object or the like. Since it is limited to only the height detection sensor, the detection operation of the other grass height detection sensors can be continuously performed.

As shown in FIGS. 7 and 8, inside the pair of left and right driving rear wheels 1L, 1R, the driving rear wheels 1L, 1R located on the turning center side during turning are lifted from the ground. It can move up and down between a descending state in which it descends and an ascending state in which the driven rear wheels 1L, 1R located on the turning center side after the turning is completed so as to contact the ground, and form the turning center in the descending state. A pair of left and right lifting type grounding bodies 9 are attached to the vehicle body V via a grounding mechanism.
The grounding portion 9A of the liftable grounding body 9 grounded on the ground is supported by the base end side of the liftable grounding body 9 so as to be rotatable around a vertical axis. The grounding mechanism attaches the bent portions of the pair of left and right U-shaped links 4 to the drive case 3 so as to be swingable around respective fulcrums P1 and P2, and attaches a vertically movable grounding body 9 to one end of the link 4. A spring 5 for urging the liftable grounding body 9 upward is attached to the other end, and the other end of the link 4 is grounded against the urging force of the spring 5. And a cam mechanism 6 for swinging operation.

The cam mechanism 6 includes a cam 6A and a cam 6A.
And a grounding motor 8 connected to the gear 7, and the cam 6A
Each time the vehicle rotates, the pair of left and right driving ground wheels 9 on the side of the lifting / lowering grounding body 9 are respectively driven by the pair of left and right lifting ground members 9.
The lowering state in which the lowering wheel L, 1R is lowered so as to levitate, and the ascending state in which the raised rear wheels 1L, 1R are raised so as to contact the ground, are alternately repeated.

As shown in FIG. 1, a control device H using a microcomputer is provided. The control device H includes the turf height detection sensors S1, S2, S3, S4, the potentiometer G, the geomagnetic sensor S0, And a signal from the encoder 14. The control device H outputs drive signals to the steering motor M1, the sensor swing motor m, and the grounding motor 8. The control device H is connected to a memory MEM for storing information.

The memory MEM and the geomagnetic sensor S
0, the direction of the first work step K1 in which the worker turns the vehicle body V at the start of the work, that is, the direction indicated by the boundary L between the unprocessed work place A and the processed work place B (see FIG. 3). and by storing in the memory MEM as a reference azimuth theta ₀ the angle theta between the geomagnetic direction J of the geomagnetic sensor S0 detects the direction indicated by the boundary L of the processed work locations B and untreated work areas a Reference azimuth setting means 10 for setting as the reference azimuth is configured.

Further, using the control device H, a detection value of the potentiometer G (hereinafter, sometimes referred to as an output voltage) is preset based on the information of the turf presence / absence detecting means 22 and the potentiometer G. A boundary detection unit 100 that determines a boundary L between the unprocessed work site A and the processed work site B based on the detection information of the turf presence / absence detection unit 22 each time the plurality of set values are obtained; The boundary detection means 100 determines the output voltage of the potentiometer G when the turf presence / absence detection means 22 has moved most to the unprocessed work place A side,
The plurality of setting values are set by dividing the output voltage of the potentiometer G when it is most moved to the side.

Hereinafter, as shown in FIG. 9, a turf presence detecting means 22 on the left side in the traveling direction, that is, a pair of turf height detecting sensors S
A case where the boundary is detected using S1, S2 will be specifically described. The output voltage of the potentiometer G when the pair of turf height detection sensors S1 and S2 is most moved to the unprocessed work site A (Py position) is 4.0 V, and conversely, the output voltage is the most toward the processed work site B. The standard condition is set so that the output voltage of the potentiometer G at the time of movement (the position of Px) becomes 1.0 V. Then, the position of Px and Py
The width of the unit at the time of dividing into 10 equal parts is set to α, and four sections of width 2α are set at the center except for the part of the width α at both ends, and the center position of each section is set to a plurality. Value P1,
Correspond to P2, P3 and P4. Therefore, the set value P
The output voltages under the standard conditions of 1, P2, P3, and P4 are 1.6 V, 2.2 V, 2.8 V, and 3.4 V, respectively, in ascending order.
become. However, in practice, the values of the output voltages deviate from the values of the standard conditions due to an error in mounting the potentiometer G to the swing shaft during assembly of the device, a mechanical error in the swing mechanism 23, and the like.

Each time the vehicle V travels a certain distance,
The turf presence / absence detecting means 22 starts from one end Px or Py of the moving range and sets the four set values P1, P2, P
The one-way moving operation is performed until the other end Py or Px is reached after passing through the positions P3 and P4. Meanwhile, the first set value P among the four set values P1, P2, P3, and P4
When the turf height detection sensor S2 moves to the position 1
The data D7 is sampled, and the data D3 is sampled by the turf height detection sensor S1 on the left side (see FIG. 2). Thereafter, the second set value P2
, D5 and D1 are sampled at the position of the third set value P3, D4 and D0 are sampled at the position of the fourth set value P4, and further, in the section of the width α on the lower side in the moving direction. When the data is moved to the above, the eight sampled data D0 to D7 are replaced with new turf presence data D0 to D7.
7 (see FIG. 11). At this time, eight turf presence / absence data D8 to D15 are sampled and updated by a pair of turf height detection sensors S3 and S4 on the right side in the traveling direction which are not used for boundary detection.

In the eight turf presence / absence data D0 to D7 obtained as described above, the bit position of the data "1" of the unprocessed work site A closest to the processed work site B side and the bit position adjacent thereto are displayed. The position of the middle of the bit position of the data “0” of the processed work place B closest to the unprocessed work place A is determined as the position of the boundary L.

Further, the vehicle body V along the boundary L determined by the boundary detection means 100 by the control device H.
A control means H for executing steering control for operating the steering motor M1 so that the vehicle travels.
Next, the steering control by the control means H will be described. The pair of turf height detection sensors determined as a proper steering position in the vehicle width direction (that is, a reference position in the vehicle width direction). The center position of S1, S2 or S3, S4, that is, the intermediate position between bit D3 and bit D4 of the eight turf presence / absence data D0 to D7 is shifted with respect to the position of the boundary L determined above. Since the deviation amount becomes the position deviation X of the steering position, the steering motor M1 is controlled so that the position deviation X becomes zero so that the proper steering position travels along the boundary L. Control the steering. Note that the direction of the deviation is defined so that the position deviation X becomes negative when the vehicle body V is shifted toward the unprocessed work site A. Therefore, if the positional deviation X is negative, the vehicle body V is corrected and steered toward the processed work site B (the left side in the traveling direction in FIG. 3), and if the positional deviation X is positive, the vehicle body V is uncorrected. A
The steering is corrected to the side (in FIG. 3, the right side in the traveling direction).

Next, the control operation of the control device H will be described with reference to the flowcharts shown in FIGS. First, when the control is started, a process of setting a plurality of set values P1 to P4, which are detection positions of grass presence detection, is performed. Next, the initial setting and stored in the reference orientation theta ₀ a direction toward the vehicle body V in the traveling start, adjust the steering direction of the front wheels 1F to this reference direction theta _0. When running is started, 16 turf presence / absence data D0 are provided for every certain running distance.
~ D15 are sampled and updated. And this one
The position of the boundary L is detected as described above based on the boundary detection data D0 to D7 of the six data D0 to D15, and the position deviation X with respect to the proper steering position of the vehicle body V is detected.
Is detected.

Next, the azimuth deviation Δθ = θ−θ ₀ is calculated from the difference between the current detected azimuth θ and the reference azimuth θ ₀ . And
The position deviation X and the azimuth deviation Δθ are respectively multiplied by predetermined gain coefficients p and q to obtain a steering angle θ _ST by the following equation, and the steering operation is performed at the steering angle θ _ST .

[0025]

Equation 1 θ _ST = p · X + q · Δθ

Then, the flow from the update of the turf presence / absence data D0 to D15 for each fixed distance travel to the steering operation at the steering angle θ _ST is repeated until the vehicle body V detects the headland.

If it is detected that the headland has been reached, it is further determined whether or not the traveled route is the final travel. If the travel is the final travel, the work is terminated.
If it is not the final stroke, the driving rear wheels 1L, 1R
The vehicle body V is turned to the unprocessed work site A side by driving the drive rear wheels 1L and 1R on the non-turn center side while operating the steering in the turning direction with the liftable grounding body 9 on one side as the turning center. Then, in the next work process, the flow from the update of the turf presence / absence data D0 to D15 for each fixed distance travel to the steering operation at the steering angle θ _ST is repeated until the vehicle body V detects the headland. . At the time of the turning operation, the direction of the vehicle body V is confirmed by the geomagnetic sensor S0, information indicating whether the vehicle has turned 180 °, and the driving rear wheels 1L, 1L, It is determined from the travel distance of 1R that the vehicle has moved to the next work process.

The detection of the headland will be described with reference to FIG. The headland is cut with the cutting width M of the rotary blade 2 for lawn mowing, and the lawn height detecting sensors S1, S2, S
Assuming that the detection distance of the detection target to the detection target in S3 and S4 is d, the turf height detection sensors S1, S2, S3, and S4 are positioned at the front end of the headland to detect the absence of turf, and then, The distance traveled before detecting the turf at the front end of the headland is M
−d. The turf height detection sensors S1, S1
2, grass presence data D0 detected by S3, S4
In D15, data "0" should occupy the majority. Therefore, assuming that the time required for the lawn height detection sensors S1, S2, S3, and S4 to perform one-way scanning in the width direction of the vehicle body in the moving range is t, and the traveling speed of the vehicle body V is v, the vehicle travels a distance of v × t. Turf height detection sensors S1, S2, S3, S4
Turf presence data is sampled once, so that the maximum number of times turf presence data is sampled while traveling the distance Md is obtained by the following equation.

[0029]

(M−d) ≧ n × v × t

Therefore, every time the vehicle travels for the predetermined distance, eight pieces of turf presence / absence data D0 for steering detected by a pair of turf height detection sensors S1 and S2 on the processed work site B side.
D7, a pair of turf height detection sensors S on the unprocessed work site A side
3, eight turf presence / absence data D8- detected by S4
D16 is added to obtain 16 pieces of turf presence / absence data D0 to D15. For each of the 16 pieces of turf presence / absence data D0 to D15 in the past n times including the present time, “for each data bit D0 to D15” 1 ", that is, a logical sum operation is performed on the data with grass. That is, if there is at least one "1", i.e., turf data, among the n times of turf presence data, the data bits D0 to D15 are "1", i.e., turf data. If the number of data with grass is less than a certain value (for example, 4) among the 16 grass presence / absence data D0 to D15 after the OR operation, it is determined that the vehicle has traveled to the headland.

In the work steps other than the last step, the boundary is determined by the lawn height detection sensors S1, S2 or S3, S4 located on the processed work value B side as described above.
A deviation X of the proper steering position of the vehicle body V with respect to this boundary is calculated and the steering control is performed so that the deviation X becomes 0. However, if it is known in advance that this is the final work stroke, the final stroke is determined. When the vehicle travels, another steering control is executed.
That is, the turf height detection sensor S on the left side in the traveling direction of the vehicle body V
1, S2 and turf height detection sensors S3, S on the right side in the traveling direction
After determining the boundary between the unprocessed work site A and the processed work site B, the deviation X of the proper steering position of the vehicle body V with respect to each boundary is calculated. The steering control is performed while maintaining the balance so that
Therefore, in this case, the boundary detecting means 100 determines the boundary L on each of the left and right sides of the vehicle body, and the control means H determines the boundary L on each of the right and left sides of the vehicle body determined by the boundary detecting means 100. The left / right deviation between the position of the boundary L in the lateral direction of the vehicle body and the reference position in the lateral direction of the vehicle body V is obtained, and the steering control is executed so that the magnitude of the lateral deviation is substantially the same. It is configured to Incidentally, such control has an advantage that the possibility of uncut leaves is reduced as compared with the case where the steering is performed according to the information of only one sensor.

Further, regarding the detection of the last stroke, FIG.
3 will be described. As described above, a pair of turf height detection sensors S3 and
Eight grass presence / absence data D8 to D1 detected by S4
In step 5, if the grassless data "0" always exists at the data position on the unprocessed work site A side until the end of the travel, the travel is determined to be the last travel. Specifically, eight turf presence / absence data D8 to D1
The unprocessed work site A side is set in the negative direction with reference to the center position of No. 5 (the middle position between D11 and D12), and the position of the turf presence data “1” located closest to the unprocessed work site A side Is determined as a boundary position between the unprocessed work site A and the processed work site on the opposite side, and a variable N is calculated from the value of the boundary position by the following equation.

[0033]

## EQU3 ## N = 4- (boundary position)

Then, the variable Nmax for determination, which is reset at the start of traveling of one work stroke, and the variable N calculated every time the vehicle travels for a certain distance are successively compared.
Is larger, the value of the variable Nmax for determination is replaced with the value of the variable N, and the headland is detected and 1
When the traveling of one work process is completed, the variable N
If the value of max is less than 8 (Nmax <8), the traveled work stroke is determined to be the last stroke.

[Another Embodiment] In the above embodiment, turf presence detecting means 2 for detecting the presence or absence of turf is provided.
2 is a pair of turf height detection sensors S1,
Although S2, S3, and S4 are used, the number of sensors such as a single turf height detection sensor and three turf height detection sensors is appropriately changed. In addition, the operating means 23 is also configured to be moved by a swing mechanism that swings around the vertical axis.
The mechanism for the movement is not limited to the swing mechanism, and the movement may be linear. Also, the position detecting means G
Are not limited to potentiometers.

In the above embodiment, four detection positions are set as the detection positions at which the detection value of the position detecting means G reaches a preset set value. However, the number of the set values depends on the required detection accuracy. It can be increased or decreased or changed as appropriate according to the situation such as. And, with the change of the number of the setting values,
The number of turf presence / absence data in the vehicle width direction obtained by the turf presence / absence detecting means 22 is changed.

In the above embodiment, the present invention is applied to a lawn mowing vehicle. However, the present invention can be applied to other mowing vehicles.

In the claims, reference numerals are provided 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 a block diagram of a control configuration.

FIG. 2 is a plan view of turf presence / absence detection means and operation means.

FIG. 3 is an explanatory diagram of a work mode.

FIG. 4 is a schematic plan view of a vehicle body.

FIG. 5 is a schematic side view of a vehicle body.

FIG. 6 is a side view of the turf presence detecting means.

FIG. 7 is a rear view of the turning mechanism.

FIG. 8 is an explanatory diagram of the operation of the turning mechanism.

FIG. 9 is an explanatory diagram of the operation of the boundary detecting means.

FIG. 10 is a flowchart of a control operation.

FIG. 11 is a flowchart of a control operation.

FIG. 12 is an explanatory diagram of headland detection.

FIG. 13 is an explanatory diagram of detection of a final stroke.

[Explanation of symbols]

 2 Lawn mowing part A Unprocessed work place B Treated work place H Control means L Boundary M1 Steering operation means V Body 100 Boundary detection means

Claims (1)

(57) [Claims] 1. The lawn is cut with a set cutting width as the vehicle runs.
Mowing unit (2), the untreated work locations based on the presence or absence of grass (A) and the treated work areas (B) boundary detection means for determining the boundaries (L) of the (100), the boundary detecting means (10
0) along the boundary (L) determined by the vehicle body (V)
To operate the steering operation means (M1) so that the vehicle runs.
A lawn mowing vehicle provided with control means (H) for executing direction control , wherein the boundary detecting means (100) is provided on each of the left and right sides of the vehicle body.
The control means (H) is configured to determine the boundary (L).
Vehicle body at the boundary (L) on each of the left and right sides of the vehicle body
The position in the width direction and the base in the width direction of the vehicle body (V)
Find the left / right deviation from the reference position and calculate the magnitude of the left / right deviation.
And a lawn mowing vehicle configured to execute the steering control so that the driving force is substantially the same.