JP2014187951A - Autonomous mobile lawn mower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomous mobile lawn mower which efficiently mows the lawn growing in a designated field and preferably prevents leaving of unmown lawn.SOLUTION: A lawn mower 10 moves to a first orientation, then, moves to the orientation opposite to the first orientation after moving by the predetermined distance along a borderline 40 if it collides with the borderline 40. It can therefore certainly move in the field in every hole and corner efficiently, even if the borderline 40 of the designated field to mow is intricately indented. In other words, the lawn mower 10 which can efficiently mow the lawn 34 growing in the designated field and preferably prevents leaving of unmown lawn can be provided.

Description

  The present invention relates to an improvement of an autonomously moving lawn mower that determines a moving path by itself and moves on a moving surface, and mows grass growing on the moving surface.

  There has been proposed an autonomously moving lawn mower that determines a moving route by itself and moves on the moving surface and mows the lawn growing on the moving surface. For example, an unmanned traveling lawn mower described in Patent Document 1 is an example. According to this technique, by performing lawn mowing work by performing straight control and turning control based on detection results of a movement distance sensor, a direction sensor, an obstacle sensor, and the like provided in the vehicle body, a certain section of the field It is said that the lawn can be automatically mowered to save labor.

JP-A-6-141614

  However, the conventional autonomously moving lawn mower has a problem in that it cannot always move efficiently throughout the area to be mowered. That is, depending on the area to be mowing, there may be a case where the boundary line of the area is intricately complicated. In such a case, the conventional technique efficiently uses the lawn growing in the area. Therefore, it has been difficult to appropriately cut and prevent uncut portions.

  The present invention has been made against the background of the above circumstances, and its purpose is to autonomously mow the lawn growing in the target area and to suitably prevent uncutting. It is to provide a mobile lawn mower.

  In order to achieve such an object, the gist of the first aspect of the present invention is that, within a region where a boundary line has been defined in advance, the movement route is determined by the own machine, and at least one pair of drive wheels is within the region. An autonomously moving lawn mower that moves on the moving surface and mows the lawn that grows on the moving surface, a drive unit that drives the pair of wheels, and a boundary line that determines the presence of the boundary line A determination unit; an azimuth detection unit that detects an azimuth directed by the autonomous mobile lawn mower; a distance detection unit that detects a distance traveled by the autonomous mobile lawn mower; and the autonomous mobile lawn mower by the drive unit. The boundary line is detected by the boundary line determination unit during the movement of the autonomous mobile lawn mower directed at the first direction and the first movement control unit. If determined, the autonomous A second movement control unit that moves the dynamic lawn mower along the boundary line; and the autonomous movement type lawn mower moves along the boundary line to thereby move the autonomous movement type by the first movement control unit. When the lawn mower moves a predetermined distance in a direction perpendicular to the first azimuth from the trajectory of the lawn mower, the autonomously moving lawn mower is moved by the drive unit in a direction opposite to the first azimuth. A third movement control unit is provided.

  As described above, according to the first invention, after the autonomous mobile lawn mower moves in the first direction and hits the boundary line, it moves a predetermined distance along the boundary line. Since the movement is directed in the direction opposite to the first direction, even if the boundary line of the area to be mowing is intricately complicated, the efficiency is not necessarily limited throughout the area. Can be moved. In other words, it is possible to provide an autonomously moving lawn mower that efficiently cuts lawn that grows in a target region and prevents uncutting.

  The gist of the second invention subordinate to the first invention is that the second movement control unit is configured to start the movement of the autonomous mobile lawn mower directed to the first direction after the boundary is moved. When the presence of the boundary line is first determined by the line determination unit, the autonomous mobile lawn mower is moved by the drive unit, and the movement trajectory of the autonomous mobile lawn mower by the first movement control unit and the boundary It is moved along the boundary line in a direction in which the line forms an obtuse angle.

  The gist of the third invention subordinate to the first invention or the second invention is that the first movement control unit, when a predetermined condition is satisfied in the movement of the autonomous mobile lawn mower, The azimuth that forms a predetermined angle with respect to the first azimuth is used as a new first azimuth, and the autonomously moving lawn mower is moved by the drive unit in the direction of the new first azimuth. .

  The gist of the fourth invention subordinate to the third invention is that the first movement control unit starts the movement of the autonomous mobile lawn mower along the boundary line by the second movement control unit. Then, when the autonomous mobile lawn mower moves at a specified distance or for a specified time, the first movement control unit moves the autonomous mobile lawn mower from the movement trajectory in a direction perpendicular to the first direction. If it has not moved for a predetermined distance, the driving unit causes the autonomous mobile lawn mower to move to the new first direction, with the direction that forms a predetermined angle with respect to the first direction as the new first direction. It moves in the direction of one direction.

  The gist of the fifth invention according to any one of the first to fourth inventions is that the boundary line emits a predetermined electromagnetic wave, and the boundary line determination unit is based on the boundary line. The presence of the boundary line is determined by detecting a predetermined electromagnetic wave emitted.

  The gist of the sixth invention, which is dependent on the fifth invention, is that the boundary line determination unit determines the presence of the boundary line when the intensity of the detected electromagnetic wave exceeds a specified reference value. To do.

  The gist of the seventh invention according to any one of the first to sixth inventions is a turf detection unit for detecting the presence of a grass of a predetermined length or longer growing on the moving surface, and its turf detection. And a lawn mowing completion determining unit that determines completion of lawn mowing in the region when the presence of the lawn is not detected by the unit for a predetermined time or more.

  The gist of the eighth invention according to any one of the first to seventh inventions is that the driving unit immediately after the start of mowing in the area or immediately before the completion of mowing in the area. Thus, the autonomous mobile lawn mower is provided with a boundary movement control unit for moving the autonomous lawn mower at least once along the boundary line.

It is a block diagram which illustrates the principal part of the structure with which the autonomous mobile lawn mower which is one Example of this invention was equipped. It is a schematic side view explaining the structure of the autonomous mobile lawn mower of FIG. It is a functional block diagram explaining the principal part of the control function with which CPU of the autonomous mobile lawn mower of FIG. 1 was equipped. It is a figure which shows an example of the movement control of the lawn mower 10 by CPU of the autonomous mobile lawn mower of FIG. It is a figure which shows another example of the movement control of the lawn mower 10 by CPU of the autonomous mobile lawn mower of FIG. It is a figure which shows another example of the movement control of the lawn mower 10 by CPU of the autonomous mobile lawn mower of FIG. It is a figure which shows another example of the movement control of the lawn mower 10 by CPU of the autonomous mobile lawn mower of FIG. It is a figure which shows another example of the movement control of the lawn mower 10 by CPU of the autonomous mobile lawn mower of FIG. It is a flowchart explaining the principal part of an example of the autonomous movement control by CPU of the autonomous mobile lawn mower of FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram illustrating a main part of a configuration provided in an autonomous mobile lawn mower 10 according to an embodiment of the present invention. As shown in FIG. 1, an autonomous mobile lawn mower 10 (hereinafter simply referred to as a lawn mower 10) according to the present embodiment includes a CPU 12 that is a central processing unit, a ROM 14 that is a read-only memory, and a read / write as needed. RAM16 which is memory, the memory | storage part 18, the lawn mower 20, the wheel drive part 22, the boundary line determination part 24, the azimuth | direction detection part 26, the distance detection part 28, and the turf detection part 30 are provided. It is configured. The CPU 12 is a so-called microcomputer that processes and controls electronic information based on a predetermined program stored in advance in the ROM 14 while using the temporary storage function of the RAM 16. The storage unit 18 is a well-known storage device such as a flash memory, for example, and stores various types of information related to the control of the lawn mower 10. The lawn mower 10 uses the electric energy supplied from a battery (not shown) to determine the movement path by the CPU 12 by the process of the CPU 12, and moves the ground 32 within the movement area (see FIG. 2). This is an automatic lawn mowing robot that mows the lawn 34 growing on the grass.

  FIG. 2 is a schematic side view illustrating the configuration of the lawn mower 10. As shown in FIG. 2, the lawn mower 10 according to the present embodiment moves relatively on the ground 32, which is a moving surface having a substantially planar shape (horizontal plane), for example, and the lawn growing on the ground 32. Mow 34. The lawn mowing apparatus 20 is preferably a well-known reel type (clippers type) in which a plurality of spirally curved reel blades are rotated around a horizontal axis and the grass 34 is trimmed by rubbing with a fixed receiving blade. ) Lawn mowing mechanism, which is a well-known drum-type lawn mowing mechanism with a drum-like rotary blade, or a well-known wire-type lawn mowing mechanism that mows the lawn 34 by rotating the wire. Also good. The lawn 34 to be mowed by the lawn mower 20 (the lawn mower 10) is a broad lawn grass that grows on a so-called lawn, and is not limited to a specific type of plant.

  The wheel drive unit 22 drives a pair of drive wheels 36 provided in the lawn mower 10 based on a command from the CPU 12. Such a pair of drive wheels 36 is preferably configured such that the rotation thereof is individually controlled by the wheel drive unit 22 and the rotation direction thereof is changed. In the lawn mower 10, the rotation direction of each driving wheel 36 is appropriately changed by the wheel driving unit 22 and the driving wheel 36 is driven, so that a plane that is parallel to the ground 32 on the ground 32. It can be moved in any direction of 360 °. The lawn mower 10 includes at least one auxiliary wheel 38 in addition to the pair of drive wheels 36. The auxiliary wheel 38 functions as an auxiliary wheel (non-driving wheel) for supporting three points by being brought into contact with the ground 32 when the lawnmower 10 is moved. Preferably, two or more auxiliary wheels 38 may be provided.

  By providing the drive mechanism as described above, the lawn mower 10 determines the movement route by itself within a region where the boundary line 40 (see, for example, FIGS. 4 to 8) is defined in advance. Then, the pair of drive wheels 36 moves on the moving surface in the region. The boundary line 40 defines a boundary between a region to be lawn mowered by the lawn mower 10 and other regions. The boundary line 40 is, for example, an electric wire embedded in the ground 32, and a predetermined current (for example, an alternating current of about 100 kHz) is passed therethrough, whereby a predetermined electromagnetic wave (electromagnetic wave having a predetermined frequency) is generated around the boundary line 40. Are to be released. The boundary line determination unit 24 determines the presence of the boundary line 40 when the lawnmower 10 moves within the region. For example, the presence of the boundary line 40 is determined by detecting an electromagnetic wave having a predetermined frequency emitted from the boundary line 40 when a current flows through the boundary line 40. Preferably, the presence of the boundary line 40 is determined when the intensity of the detected electromagnetic wave exceeds a specified reference value. That is, the boundary line determination unit 24 includes a coil or the like for detecting an electromagnetic wave having a predetermined frequency emitted from the electric wire embedded in the ground 32.

  The azimuth detecting unit 26 detects the azimuth directed by the lawn mower 10, that is, the azimuth (direction) corresponding to the forward direction of the aircraft. For example, an orientation (four positive orientations) based on geomagnetism is detected. That is, the azimuth detecting unit 26 preferably includes an electronic compass (electromagnetic compass) for detecting an azimuth based on geomagnetism. Alternatively, in a configuration in which a plurality of wireless tags (IC chips) are fixed at predetermined positions in the region, the azimuth detecting unit 26 detects the positions of the plurality of wireless tags with respect to the lawn mower 10, thereby The direction to which the machine 10 is directed may be detected. That is, the azimuth detecting unit 26 may detect an absolute azimuth like an azimuth based on geomagnetism, or may detect a relative azimuth such as an azimuth with respect to the region.

  The distance detector 28 detects the distance that the lawn mower 10 has moved. Preferably, by detecting the amount of rotation of the pair of drive wheels 36, the distance that the lawn mower 10 has moved on the ground 32 by the drive of the drive wheels 36 is detected. In other words, the distance detection unit 28 preferably includes a wheel encoder that detects the amount of rotation of each of the pair of wheels 36 driven by the wheel drive unit 22. This wheel encoder is, for example, an optical or magnetic rotary encoder.

  The turf detection unit 30 detects the presence of a turf 34 having a predetermined length or more growing on the ground 32 that is a moving surface of the lawn mower 10. Preferably, as shown in FIG. 2, it is determined whether or not the lawn mower 10 has a lawn 34 having a predetermined length or more in front of the direction of travel (forward direction). The lawn detection unit 30 preferably includes an optical sensor or the like that detects the presence or absence of an object at a predetermined height from the ground 32 in front of the lawn mower 10 in the traveling direction. That is, the turf detection unit 30 does not necessarily detect the turf 34 as a plant separately from other objects, and has a predetermined height from the ground 32 in the ground 32 that is the moving surface of the lawn mower 10. Any device may be used as long as it detects the presence of an object at the position.

  Since the lawn mower 10 has the above-described configuration, a movement path is determined by the own machine within the area surrounded by the boundary line 40, and the pair of driving wheels 36 determines that the lawn mower 10 is within the area. Is moved on the ground 32 and the lawn mowing device 20 cuts the lawn 34 growing on the ground 32. That is, when the lawn mower 10 moves on the ground 32, the lawn 34 growing on the ground 32 is mowed along the movement trajectory. Specific examples will be described below with reference to FIGS.

  FIG. 3 is a functional block diagram for explaining a main part of the control function provided in the CPU 12 of the lawn mower 10. The first movement control unit 50 shown in FIG. 3 moves (directly) the lawn mower 10 in the first direction by the wheel driving unit 22 when the lawn mower 10 moves in the region. Take control. The first azimuth is, for example, a certain azimuth detected by the azimuth detecting unit 26. When the lawn mower 10 moves in the first direction, the lawn mower 10 The vehicle travels straight in the first direction (for example, a constant azimuth angle of 40 ° in the 360 ° direction). That is, the first movement control unit 50 preferably uses the wheel driving unit 22 to move the lawn mower 10 to the first direction, which is a fixed direction, based on the detection result by the direction detection unit 26. Control to move in the direction.

  FIG. 4 is a diagram showing an example of movement control of the lawn mower 10 by the CPU 12 of the lawn mower 10, and the movement locus of the lawn mower 10 is indicated by a broken line arrow. As shown in FIG. 4, the first movement control unit 50 preferably starts movement of the lawn mower 10 from the point 1A which is a start point immediately after the start of lawn mowing in the region, and then will be described later. The lawn mower 10 is pointed at the first direction, which is a constant direction, by the wheel drive unit 22 until the presence of the boundary line 40 is determined at the point 1B (coincides with the boundary line 40). And control to move (go straight).

  The second movement control unit 52 shown in FIG. 3, when the boundary line determination unit 24 determines the presence of the boundary line 40 during the movement of the lawn mower 10 directed in the first direction, The lawn mower 10 is moved along the boundary line 40 by the wheel drive unit 22. In other words, during the movement of the lawn mower 10 that is directed to the first direction under the control of the first movement control unit 50, the presence of the boundary line 40 is determined in front of the traveling direction (the boundary line 40). The pair of driving wheels by the wheel driving unit 22 based on the detection result by the boundary line determination unit 24 so that the lawn mower 10 moves along the boundary line 40. The drive of 36 is controlled. The presence of the boundary line 40 in front of the lawn mower 10 in the traveling direction is determined, for example, when the intensity of the predetermined electromagnetic wave detected by the boundary line determination unit 24 is equal to or higher than a predetermined value. Here, moving along the boundary line 40 means that the temporal transition of the direction of travel of the lawn mower 10 substantially matches the shape (curvature) of the boundary line 40. In the movement of the lawn mower 10 along the boundary line 40, the lawn mower 10 is preferably moved so that the body of the lawn mower 10 is always inside the boundary line 40 (on the side of the area targeted for lawn mowing). However, in a mode in which there is no obstacle such as a ridge between the region and the outside thereof, in the movement of the lawn mower 10 along the boundary line 40, a part of the body of the lawn mower 10 is the boundary. It may protrude outside the line 40.

  Preferably, the second movement control unit 52 first determines the presence of the boundary line 40 by the boundary line determination unit 24 after the movement of the lawn mower 10 pointing in the first direction is started. In this case, the wheel drive unit 22 causes the lawn mower 10 to move in the direction in which the trajectory of the lawn mower 10 by the first movement control unit 50 and the boundary line 40 form an obtuse angle. Move along. In the present embodiment, the angle between the trajectory of the lawn mower 10 and the boundary line 40 as a reference for such determination is an angle formed on the lawn mower 10 side, that is, the front side with respect to the boundary line 40. is there. In other words, when it is determined that the lawn mower 10 has first hit the boundary line 40 after the movement of the lawn mower 10 within the region is started, the wheel drive unit 22 causes the lawn mower 10 to be moved there. After the direction is changed in a direction that forms an obtuse angle with the movement trajectory up to, control is performed to move along the borderline 40 that has been hit. For example, in the example shown in FIG. 4, the boundary line 40 was first hit at the point 1B during the movement of the lawn mower 10 directed in the first direction, as shown in an enlarged view of the part surrounded by a broken line. In this case, as a mode of moving along the boundary line 40, (a) a mode in which the angle between the first azimuth and the boundary line 40 proceeds in a direction that forms an obtuse angle θ1, and (b) the first azimuth and the boundary line. The lawn mower 10 is preferably directed in the direction in which the angle between the first orientation and the boundary line 40 forms the obtuse angle θ1, and the boundary between the first direction and the boundary line 40 is formed. The lawn mower 10 is moved along the line 40. Alternatively, the second movement control unit 52 first determines the presence of the boundary line 40 by the boundary line determination unit 24 after the movement of the lawn mower 10 directed to the first direction is started. In this case, the lawn mower 10 is moved by the wheel drive unit 22 to the boundary line 40 in the direction in which the movement locus of the lawn mower 10 by the first movement control unit 50 and the boundary line 40 form an acute angle θ2. It may be moved along, or may be moved arbitrarily (at random) in either the direction forming the obtuse angle θ1 or the direction forming the acute angle θ2.

  The third movement control unit 54 shown in FIG. 3 moves the lawn mower 10 along the boundary line 40, so that the first direction is determined based on the movement trajectory of the lawn mower 10 by the first movement control unit 50. When the vehicle moves by a predetermined distance Δd in a direction perpendicular to the direction, the wheel drive unit 22 moves the lawn mower 10 in a direction opposite to the first direction. The determination of the movement distance is performed based on the detection result by the distance detection unit 28, for example. As shown in FIG. 4, the lawn mower 10 is moved from the point 1B along the boundary line 40, and the movement trajectory of the lawn mower 10 by the first movement control unit 50, that is, the movement trajectory from the point 1A to the point 1B. If it is determined at point 1C that the vehicle has moved a predetermined distance Δd in a direction perpendicular to the movement trajectory, the lawn mower 10 is moved from the point 1C in the direction opposite to the first direction. Let The predetermined distance Δd preferably corresponds to a width (a cutting width in a direction perpendicular to the traveling direction) that the lawn mower 10 can mow the lawn 34, for example, in the first direction. In advance, a part of the width is overlapped by a corresponding movement locus and a movement locus corresponding to the opposite direction of the first orientation after movement along the boundary line 40 from the movement locus. It is determined. The movement trajectory of the lawn mower 10 by the first movement control unit 50, that is, the movement distance from the direction directed to the first azimuth to the direction perpendicular to the lawn mower 10 is v, the movement speed of the lawn mower 10 at each time t. Each direction formed by the lawn mower 10 and the first direction is represented by the following formula (1), where θ (t) is defined as θ (t). Therefore, the third movement control unit 54, when the movement distance of the lawn mower 10 from the direction directed to the first direction to the vertical direction satisfies the following expression (2), The lawn mower 10 is moved (directly moved) in the direction opposite to the first direction by the driving unit 22.

∫v · sinθ (t) dt (1)
Δd = ∫v · sin θ (t) dt (2)

  The second movement control unit 52 preferably has the boundary line 40 present by the boundary line determination unit 24 after the lawn mower 10 starts moving in the first direction or the opposite direction. Is determined, that is, when the second and subsequent determinations are made, the lawn mower 10 is moved by the wheel drive unit 22 in the movement control by the second movement control unit 52. The direction is changed in the direction opposite to the changed direction and moved along the boundary line 40. That is, in the movement control performed by the second movement control unit 52, the lawn mower 10 changes its direction to the right from the movement locus of the lawn mower 10 in the first direction or the opposite direction. In this case, in the movement control by the second movement control unit 52 this time, the lawn mower 10 is moved in the traveling direction from the movement locus of the lawn mower 10 directed in the first direction or the opposite direction. The direction is changed to the left and moved along the boundary line 40. In other words, the second movement control unit 52 preferably uses the boundary line determination unit 24 to start the movement of the lawn mower 10 in the first direction or the opposite direction. When the presence of the line 40 is determined, that is, when the second and subsequent determinations are made, as described above, regardless of whether the moving locus and the boundary line 40 form an obtuse angle or an acute angle. The lawn mower 10 is alternately turned left and right and moved along the boundary line 40 in that direction.

  FIG. 5 is a diagram showing another example of the movement control of the lawn mower 10 by the CPU 12 of the lawn mower 10, and the movement trajectory of the lawn mower 10 is indicated by broken line arrows. As shown in FIG. 5, the second movement control unit 52 is preferably configured to move the lawn mower 10 in the first direction from the starting point 2A to the point 2B. When the presence of the boundary line 40 is determined at the point 2B, the lawn mower 10 is directed (turned) in the direction in which the angle between the first direction and the boundary line 40 forms an obtuse angle, that is, in the right direction. The lawn mower 10 is moved from the point 2B toward the point 2C along the boundary line 40. Next, in the movement of the lawn mower 10 along the boundary line 40, it is determined at the point 2C that the lawn mower 10 has moved by a predetermined distance Δd in a direction perpendicular to the first direction. The lawn mower 10 is moved in the direction opposite to the first direction. When it is determined that the boundary line 40 exists at the point 2D, the second movement control unit 52 preferably turns the lawn mower 10 at the point 2B related to the previous control. The lawn mower 10 is turned in the direction opposite to the direction, that is, in the left direction, and moved along the boundary line 40. The predetermined distance Δd preferably corresponds to a movement locus corresponding to the first azimuth and a reverse azimuth of the first azimuth after movement along the boundary line 40 from the movement locus. The movement of the lawn mower 10 is determined in advance so that a part of the width over which the lawn mower 10 can mow the lawn 34 overlaps, so that the movement of the lawn mower 10 is controlled as shown in FIG. However, by performing lawn mowing by the lawn mowing apparatus 20, it is possible to suitably suppress the uncut grass of the lawn 34 growing in the area surrounded by the boundary line 40.

  The first movement control unit 50 preferably sets a new azimuth that forms a predetermined angle with respect to the first azimuth when the predetermined condition is satisfied in the movement of the lawn mower 10. As the azimuth, the lawn mower 10 is moved in the new first azimuth direction by the wheel drive unit 22. The predetermined angle is preferably 90 °. The predetermined condition is preferably that the lawn mower 10 moves a prescribed distance or a prescribed time after the lawn mower 10 starts moving along the boundary line 40 by the second movement control unit 52. At this point, the predetermined distance Δd is not moved in the direction perpendicular to the first azimuth from the movement locus of the lawn mower 10 by the first movement control unit 50. Examples of cases where such a condition is satisfied include: (a) an obstacle exists in the movement trajectory in which the lawn mower 10 moves along the boundary line 40, or the boundary line 40 is bent at a right angle or an acute angle. (B) When the lawn mower 10 moves along the boundary line 40, the movement trajectory is curved in a direction opposite to the direction of the predetermined distance Δd. There may be a case where the predetermined distance Δd cannot be moved in a direction perpendicular to the first azimuth even if the movement continues along the boundary line 40. That is, the first movement control unit 50 preferably has the lawn mower 10 moved a specified distance after the second movement control unit 52 starts moving the lawn mower 10 along the boundary line 40. Alternatively, when the predetermined distance Δd has not moved in the direction perpendicular to the first azimuth from the movement trajectory of the lawn mower 10 by the first movement control unit 50 when it has moved for a predetermined time, The lawn mower 10 is moved (directly moved) in the direction of the new first direction by the wheel driving unit 22 with the direction that forms a predetermined angle with respect to the one direction as a new first direction.

  FIG. 6 is a diagram showing still another example of the movement control of the lawn mower 10 by the CPU 12 of the lawn mower 10, and the movement trajectory of the lawn mower 10 is indicated by broken line arrows. As shown in FIG. 6, the second movement control unit 52 preferably has the boundary line 40 at the point 3G when the lawnmower 10 is moved along the boundary line 40 from the point 3F. When the vehicle has reached this corner and cannot advance in the forward direction, movement control by the first movement control unit 50 is started with the point 3G as a new start point. Preferably, as shown in FIG. 6, a direction that forms 90 ° from the point 3G to the inside of the boundary line 40 and to the first azimuth (the direction corresponding to the movement locus from the point 3A to the point 3B). The lawn mower 10 is moved (goes straight).

  By controlling the movement of the lawn mower 10 via the wheel drive unit 22 and the like under the control of the first movement control unit 50, the second movement control unit 52, and the third movement control unit 54 described above. The lawn mower 10 is moved throughout the area surrounded by the boundary line 40 that is the target of lawn mowing, and the lawn mower 20 cuts the lawn in the area. 7 and 8 are diagrams showing still another example of the movement control of the lawn mower 10 by the CPU 12 of the lawn mower 10, and the movement trajectory of the lawn mower 10 is indicated by broken-line arrows. As shown in FIGS. 7 and 8, in the movement control of the lawn mower 10 by the first movement control unit 50, the second movement control unit 52, and the third movement control unit 54, the movement from the start point S is performed. When started, the lawn mower moves in a direction perpendicular to the first azimuth by a predetermined distance Δd by movement along the boundary line 40 and directs the first azimuth or the opposite direction. Ten movements are performed alternately. That is, in the region surrounded by the boundary line 40, the parallel movement of the lawn mower 10 that directs the first direction or the opposite direction while interpolating the vertical movement of the predetermined distance Δd is repeated. The lawn mower 10 is scanned. Further, when it is impossible to proceed in the forward direction at the point R and it is also impossible to proceed in the first direction or the opposite direction, the first movement is performed with the point R as a new start point. When the movement control by the control unit 50 is resumed, parallel movement of the lawn mower 10 that is oriented in the direction perpendicular to the first direction or the opposite direction while interpolating the vertical movement of the predetermined distance Δd is performed. Repeated. As a result, the movement trajectory of the lawn mower 10 has a lattice shape (a grid pattern) in plan view as shown in FIGS. Therefore, regardless of whether the predetermined boundary line 40 is linear (rectangular) as shown in FIG. 7 or curved as shown in FIG. 8, it grows in the target region. It is possible to efficiently mow the turf 34 that is being cut and to prevent uncut residue.

  The lawn mowing completion determination unit 56 shown in FIG. 3 determines the completion of lawn mowing in the area when the lawn detection unit 30 does not detect the presence of the lawn 34 for a predetermined time or more. That is, preferably, when the lawn detection unit 30 does not detect the presence of the lawn 34 longer than a predetermined length in the forward direction (forward direction) of the lawn mower 10 for the predetermined time or longer. Determines completion of lawn mowing in the region. The boundary movement control unit 58 causes the wheel drive unit 22 to move the lawn mower 10 at least along the boundary line 40 immediately after the start of mowing in the region or immediately before the completion of mowing in the region. Move one round. That is, after the lawn mower 10 is started (started), immediately after the movement control of the lawn mower 10 is started by the first movement control unit 50 from the start point, or in the area by the lawn mower completion determination unit 56. Immediately after the completion of lawn mowing is determined, the lawn mower 10 is moved by the wheel drive unit 22 until the presence of the boundary line 40 is determined, and then moved at least one turn along the boundary line 40. The lawn mowing device 10 is used to mow the lawn 34 on the movement trajectory. As a result, it is possible to more suitably prevent uncut cutting of the grass 34 growing in the target region.

  FIG. 9 is a flowchart for explaining a main part of an example of the autonomous movement control by the CPU 12 of the lawn mower 10 and is repeatedly executed at a predetermined cycle.

  First, in step (hereinafter, step is omitted) S1, the azimuth (direction) to which the body of the lawn mower 10 is directed is acquired based on the detection result by the azimuth detection unit 26 and the like. Next, in S2, the driving of the wheel drive unit 22 is controlled, so that the lawn mower 10 is caused to go straight in the first direction, that is, the direction acquired in S1. Next, in S <b> 3, it is determined whether or not the boundary line 40 is determined in front of the lawn mower 10 in the traveling direction based on the determination result by the boundary line determination unit 24. If the determination at S3 is negative, the determination is made to wait by repeating the determination at S3. However, if the determination at S3 is affirmative, whether or not the grass 34 has been mowed for a predetermined time or longer in S4. In other words, it is determined whether or not the presence of the turf 34 has been detected continuously by the turf detector 30 for a predetermined time or more. If the determination in S4 is negative, the processing from S6 is executed. If the determination in S4 is positive, in S5, the lawn mower 10 is moved by the wheel drive unit 22 to the boundary. After being moved at least one turn along line 40, the routine is terminated.

  In S6, the direction θ when the presence of the boundary line 40 is determined in front of the lawn mower 10 in the traveling direction, that is, the direction in which the body of the lawn mower 10 is directed is detected. Next, in S <b> 7, the lawn mower 10 is moved along the boundary line 40 by the wheel drive unit 22. Regarding the control of S7, when the presence of the boundary line 40 is detected for the first time, the lawn mower 10 is turned in a direction that forms an obtuse angle with the direction detected in S6. When it is determined that the boundary line 40 is present for the second time or later, the lawn mower 10 is turned in the direction opposite to the direction change of the lawn mower 10 in the previous control. Next, in S8, the lawn mower 10 is moved along the boundary line 40, so that the lawn mower is moved in the direction perpendicular to the direction θ detected in S6 from the movement locus of the lawn mower 10 in S2. It is determined whether the machine 10 has been moved by a predetermined distance Δd. If the determination in S8 is affirmative, after the lawn mower 10 is started to go straight in S9 in the direction opposite to the direction θ detected in S6 (the direction corresponding to θ + 180 °). , S3 and subsequent processes are executed. If the determination in S8 is negative, in S10, whether or not the movement distance after the lawn mower 10 starts moving along the boundary line 40 is greater than a predetermined amount L. Is judged. If the determination in S10 is negative, the processes in and after S7 are executed again. However, if the determination in S10 is affirmative, in S11, the detection is performed inside the boundary line 40 and in S6. After the lawn mower 10 is started to go straight in the direction perpendicular to the direction θ, the processes in and after S3 are executed.

  In the above control, S2 and S9 are operations of the first movement control unit 50, S3, S6 and S7 are operations of the second movement control unit 52, and S8, S10 and S11 are operations of the third movement control unit 54. S4 corresponds to the operation of the lawn mowing completion determination unit 56, and S5 corresponds to the operation of the boundary movement control unit 58, respectively.

  Thus, according to the present embodiment, when the lawn mower 10 moves in the first direction and hits the boundary line 40, after moving a predetermined distance along the boundary line 40, Since the movement is directed in the direction opposite to the first direction, even if the boundary line 40 of the area to be mowed is intricately complicated, the efficiency is not necessarily limited throughout the area. Can be moved. That is, it is possible to provide the lawn mower 10 that efficiently cuts the lawn 34 that grows in the target region and that suitably prevents uncut residue.

  The preferred embodiments of the present invention have been described in detail with reference to the drawings. However, the present invention is not limited to these embodiments, and may be implemented in other modes.

  For example, in the above-described embodiment, the boundary line 40 that defines the lawn mowing area by the lawn mower 10 is an electric wire embedded in the ground 32, and a predetermined current is caused to flow, so that a predetermined electromagnetic wave is generated around the boundary line 40. However, it is also possible to provide a curb or the like that is one step higher than that in the area as a boundary line that defines the lawn mowing area by the lawn mower 10. In such an embodiment, the boundary determination unit 24 may detect the presence of the boundary by an optical sensor, or detect the presence when the lawnmower 10 contacts the boundary. It may be a thing. The determination of the predetermined distance Δd by the third movement control unit 54 is not necessarily performed by strict calculation such as calculating Δd based on the above-described equation (2). The direction is changed from the state of directing the direction of the first direction, and when the movement distance detected by the distance detection unit 28 after the movement along the boundary line 40 becomes approximately Δd, the first direction of the first direction is changed. Control for moving the lawn mower 10 in the opposite direction may be performed. Alternatively, the map information (map) of the area to be mowered by the lawn mower 10 is stored in the storage unit 18 or the like in advance, and the first orientation and the predetermined distance Δd determined in the map information are stored. A mode in which the movement control of the lawn mower 10 is performed based on the above is also conceivable. A sensor for detecting the height of the lawn 34 growing on the ground 32 is provided, and the timing at which the lawn mower 10 changes the direction is determined according to the height (height) of the lawn 34 detected by the sensor. You may do. In other words, the height of the lawn 34 to be cut may be detected one by one, and the movement control of the lawn mower 10 may be performed according to the height. With respect to the movement of the lawn mower 10 in the region, a mode in which the lawn mower 10 moves while performing lawn mowing and a mode in which the lawn mower 10 moves without performing lawn mowing may be switchable.

  In addition, although not illustrated one by one, the present invention is implemented with various modifications within a range not departing from the gist thereof.

  10: Autonomous mobile lawn mower, 22: Wheel drive unit, 24: Boundary line determination unit, 26: Direction detection unit, 28: Distance detection unit, 30: Grass detection unit, 32: Ground (moving surface), 34: Grass , 36: drive wheel, 40: boundary line, 50: first movement control unit, 52: second movement control unit, 54: third movement control unit, 56: lawn mowing completion determination unit, 58: boundary movement control unit

Claims (8)

Autonomous to move the grass on the moving surface by determining the moving route by itself and moving on the moving surface in the region with at least one pair of driving wheels in the area where the boundary line is defined in advance A mobile lawn mower,
A drive unit for driving the pair of wheels;
A boundary line determination unit for determining presence of the boundary line;
An azimuth detecting unit for detecting an azimuth directed by the autonomous mobile lawn mower;
A distance detector that detects the distance traveled by the autonomous mobile lawn mower;
A first movement control unit configured to move the autonomously moving lawn mower in the first direction by the driving unit;
When the boundary line determination unit determines the presence of the boundary line during the movement of the autonomous mobile lawn mower oriented in the first direction, the driving unit causes the autonomous mobile lawn mower to A second movement control unit that moves along the boundary line;
When the autonomous mobile lawn mower moves along the boundary line, and moves by a predetermined distance from the movement locus of the autonomous mobile lawn mower by the first movement control unit in a direction perpendicular to the first azimuth. The autonomous mobile lawn mower further comprises: a third movement control unit that moves the autonomous mobile lawn mower in the direction opposite to the first orientation by the drive unit. In the case where the boundary line determination unit first determines the presence of the boundary line after the movement of the autonomously moving lawn mower directed to the first direction is started, the second movement control unit The autonomously moving lawn mower is moved by the driving unit along the boundary line in a direction in which the movement line of the autonomously moving lawn mower by the first movement control unit and the boundary line form an obtuse angle. The autonomous mobile lawn mower according to claim 1. In the movement of the autonomous mobile lawn mower, when the predetermined condition is satisfied, the first movement control unit sets a direction that forms a predetermined angle with respect to the first direction as a new first direction. The autonomous mobile lawn mower according to claim 1 or 2, wherein the driving part moves the autonomous mobile lawn mower toward the new first direction. The first movement control unit moves the autonomous mobile lawn mower along the boundary line by the second movement control unit, and then moves the autonomous mobile lawn mower for a specified distance or for a specified time. When the predetermined distance has not been moved in the direction perpendicular to the first azimuth from the movement trajectory of the autonomous mobile lawn mower by the first movement control unit at the time, The azimuth | direction which makes a predetermined angle in this way is made into the said new 1st azimuth | direction, and the said autonomously moving lawn mower is moved to the new 1st azimuth | direction by the said drive part. Autonomous lawn mower. The boundary line emits a predetermined electromagnetic wave,
The autonomous mobile type according to any one of claims 1 to 4, wherein the boundary line determination unit determines presence of the boundary line by detecting a predetermined electromagnetic wave emitted from the boundary line. Lawn mower. The autonomous mobile lawn mower according to claim 5, wherein the boundary line determination unit determines the presence of the boundary line when the intensity of the detected electromagnetic wave is equal to or greater than a predetermined reference value. A turf detector that detects the presence of turf over a predetermined length growing on the moving surface;
7. A lawn mowing completion determination unit that determines completion of lawn mowing in the area when the lawn detection unit does not detect the presence of lawn for a predetermined time or longer. 7. The autonomous mobile lawn mower according to claim 1. Immediately after the start of lawn mowing in the area or immediately before the completion of lawn mowing in the area, the boundary moving control unit moves the autonomous mobile lawn mower at least one turn along the boundary line by the drive unit. The autonomous mobile lawn mower according to any one of claims 1 to 7.

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