Autonomously controlled type grass mower

Abstract

To provide an autonomously controlled type grass mower capable of reducing an operator's load.SOLUTION: A control unit selects a point (3) as a first selection point from the points (1) to (4), causes a grass mower (10) to travel straight to the first selection point, selects a point (1) as a second selection point when the grass mower reaches the first selection point, causes the grass mower (10) to travel straight to the second selection point, selects a destination (55) when the grass mower (10) reaches the second selection point, and causes the grass mower (10) to travel straight to the destination (55). Even if a work area has a complicated shape, the grass mower (10) can be quickly moved to the destination (55) in an unmanned manner.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to an autonomously controlled grass cutter that performs grass cutting work unmanned. [Background technology]

[0002] [Terminology] GPS sensor: A sensor used to receive radio waves emitted from multiple satellites and determine the coordinates of the current location. The current accuracy of GPS positioning is about 3 meters.

[0003] Orientation sensor: A sensor used to determine whether the aircraft is facing north, south, east, or west.

[0004] Protruding corner: pronounced "sumi" or "dezumi." Also called "dezuka." In the narrow sense, it is an architectural term that refers to the protruding corner at the intersection of a pair of walls. In this invention, a "protruding corner" is called a "protruding corner." Inside corner: A recessed corner at the intersection of a pair of walls. In this invention, a "recessed corner" is called an inside corner.

[0005] Advance: Moving forward. Reverse: To move backward. Straight ahead: Going straight ahead. Turn: A machine rotating or flipping while in motion. Worker: A person who cuts grass using a grass cutter, including a manager who manages the work area.

[0006] [Conventional autonomously controlled grass cutter] BACKGROUND ART Various types of autonomously controlled grass cutters have been known in the past (see, for example, Patent Document 1 (FIGS. 5, 7, and 9)).

[0007] Patent Document 1 will be explained with reference to the following figure. FIG. 16(a) is a diagram illustrating the basic operation of a conventional autonomously controlled grass cutter. As shown in FIG. 16(a), the area surrounded by boundary wire 101 is work area 102. An autonomously controlled grass cutter 103 cuts grass while autonomously traveling as shown by arrow (11). If it detects boundary wire 101 while traveling, it turns as shown by arrow (12). In this way, grass is cut in work area 102 unmanned.

[0008] However, in sunny places, grass grows quickly and the stems become thicker, while in shady places, grass grows slowly and the stems become thinner. Patent Document 1 is an invention that aims not only to cut grass unmanned, but also to cut grass in a way that suits the level of grass growth.

[0009] For this purpose, in Patent Document 1, the work area 102 is divided into several tens to several hundreds of cells 111, as shown in FIG. 16(b). 17(a), the work area 102 is divided into four small areas 105, 106, 107, and 108 by imaginary boundaries 104. The imaginary boundaries 104 pass between the cells.

[0010] Suppose the grass in small area 106 grows faster than the grass in small areas 105, 107, and 108. FIG. 17(b) is an enlarged view of part b in FIG. 17(a). As shown in FIG. 17(b), the autonomously controlled grass cutter 103 autonomously traveled in the small area 106 as indicated by the arrow (13), and passed through cell 111a among the countless cells.

[0011] Immediately afterwards, when the autonomously controlled grass cutter 103 approaches the imaginary boundary line 104, the travel control means selects one of the cells 111b to 11d different from the cell 111a, and turns to, for example, the cell 111b (arrow (14)). As a result, the autonomously controlled grass cutter 103 travels autonomously only within the small area 106.

[0012] Therefore, the technology of Patent Document 1 has the advantage that one of the small areas 105, 106, 107, and 108 can be selected and only the selected small area can be mowed.

[0013] On the other hand, the technology of Patent Document 1 has the following drawbacks. First, several tens to several hundreds of cells 111 are required. The travel control means must store the position information of these countless cells 111. This increases the storage area of ​​the travel control means. As the storage area increases, the travel control means becomes more expensive.

[0014] Secondly, the technology of Patent Document 1 assumes that the autonomously controlled grass cutter 103 is placed in a selected small area, and only discloses control after the grass cutter is placed. In FIG. 17(a), it is assumed that the small area 108 is selected when the autonomously controlled grass cutter 103 is located at the charging station 109. In this case, the worker manually moves the autonomously controlled grass cutter 103 from the charging station 109 to the small area 108.

[0015] Furthermore, for example, after mowing the small area 108, the autonomously controlled mower 103 may be moved to the small area 107 and the mowing of the small area 107 may be carried out. In this case as well, the operator manually moves the autonomously controlled brush cutter 103. During this movement, the worker cannot perform other tasks.

[0016] In order to promote the widespread use of autonomously controlled brush cutters, it is necessary to make the travel control means (i.e., the control unit) smaller and less expensive, and it is also necessary to reduce the burden on the operator. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Patent No. 5973608 Summary of the Invention [Problem to be solved by the invention]

[0018] An object of the present invention is to provide an autonomously controlled grass cutter that can reduce the size and cost of the control unit and reduce the burden on the operator. [Means for solving the problem]

[0019] The invention of claim 1 relates to an autonomously controlled grass trimmer that has a body that includes a swiveling blade, front wheels positioned in front of the blade, rear wheels positioned behind the blade, a motor that drives the rear wheels, a battery that supplies power to the motor, a wire sensor that detects an area wire that encloses a work area, and a control unit that controls the rotation of the rear wheels and the steering of the front wheels, and that travels autonomously; This autonomously controlled grass cutter further includes a GPS sensor that acquires the position coordinates of the machine, and a direction sensor that acquires direction information of the machine, the control unit is capable of operating a work mode in which the machine performs grass cutting while autonomously traveling, a return mode in which the machine returns to a charging station when the remaining voltage of the battery drops to a predetermined level, and a straight-line mode in which the machine travels straight to a destination set by an operator within the work area, In the straight-ahead mode, the control unit acquires the coordinates of a plurality of external corners on the outer hull line of the work area using the GPS sensor, calculates the distance from each external corner to the destination based on the coordinates of these external corners and the coordinates of the destination, selects the external corner closest to the destination and assigns point (1) to the coordinates of the location a predetermined distance from this external corner into the work area, selects the external corner next closest to the destination and assigns point (2) to the coordinates of the location a predetermined distance from this external corner into the work area, and assigns points (1), (2), (3), (4), etc. in this manner, and then connects the destination and points (1), (2), (3), (4), etc. from the aircraft with straight lines, excluding any of these straight lines that intersect with the outer hull line, and if the destination is included in this exclusion, it is not excluded. a first selection point with the smallest number from the list, and directing the aircraft to travel straight toward the first selection point using the direction sensor; when the aircraft reaches the first selection point, connecting the aircraft to the destination and points (1), (2), (3), (4), etc. with straight lines, excluding those lines that intersect with the shell line; if the destination is included in the excluded lines, selecting a second selection point with the smallest number from those that are not excluded, and directing the aircraft to travel straight toward the second selection point using the direction sensor; this process is repeated until the straight line connecting the aircraft to the destination no longer intersects with the shell line; and when the straight line connecting the aircraft to the destination does not intersect with the shell line, controlling the aircraft to travel straight toward the destination.

[0020] The invention of claim 2 is an autonomously controlled grass cutter that has a machine body, a swiveling cutting blade, front wheels arranged in front of the cutting blade, rear wheels arranged behind the cutting blade, a motor that drives the rear wheels, a battery that supplies power to the motor, a wire sensor that detects an area wire that encloses a work area, and a control unit that controls the rotation of the rear wheels and the steering of the front wheels, and that travels autonomously, This autonomously controlled grass cutter further includes a GPS sensor that acquires the position coordinates of the machine, and a direction sensor that acquires direction information of the machine, the control unit is capable of operating a work mode in which the machine performs grass cutting while autonomously traveling, a return mode in which the machine returns to a charging station when the remaining voltage of the battery drops to a predetermined level, and a straight-line mode in which the machine travels straight to a destination set by an operator within the work area, In the straight-ahead mode, the control unit acquires the coordinates of a plurality of external corners on the outer hull line of the work area using the GPS sensor, calculates the distance from each external corner to the destination based on the coordinates of these external corners and the coordinates of the destination, selects the external corner closest to the destination and assigns point (1) to the coordinates of the external corner a predetermined distance into the work area, selects the external corner next closest to the destination and assigns point (2) to the coordinates of the external corner a predetermined distance into the work area, and assigns points (1), (2), (3), (4), etc. in this manner, then connects the destination and points (1), (2), (3), (4), etc. from the aircraft with straight lines, excludes those lines that intersect with the outer hull line, and when the destination is included in the excluded lines, selects a first selected point with the smallest number from those that are not excluded, and directs the aircraft to travel straight toward the first selected point using the direction sensor. and while traveling in a straight line, a straight line is always drawn from the aircraft to the destination, and if this line no longer intersects with the hull line, the aircraft is made to travel in a straight line toward the destination; if the line connecting the aircraft to the destination continues to intersect with the hull line, when the aircraft reaches the first selected point, a straight line is drawn from the aircraft to points (1), (2), (3), (4), etc., a second selected point with the smallest number is selected, and the aircraft is made to travel in a straight line toward the second selected point using the orientation sensor; while traveling in a straight line, a straight line is always drawn from the aircraft to the destination, and if this line no longer intersects with the hull line, the aircraft is made to travel in a straight line toward the destination; and if the line connecting the aircraft to the destination continues to intersect with the hull line, the aircraft is made to continue traveling in a straight line toward the second selected point; this is repeated until the straight line connecting the aircraft to the destination no longer intersects with the hull line.

[0021] The invention according to claim 3 is the autonomously controlled brush cutter according to claim 1 or claim 2, The control unit is capable of performing concentrated mowing operation in addition to the work mode, the return mode, and the straight mode, In the concentrated mowing operation, the operator sets a work circle of any diameter centered on the destination, and the control unit causes the machine to drive autonomously after arriving at the destination, and when the machine moves away from the destination by the radius of the work circle, causes the machine to drive autonomously while turning toward the destination, and thereafter repeatedly causes the machine to turn toward the destination when the machine moves away from the destination by the radius of the work circle. [Effects of the Invention]

[0022] In the invention according to claim 1, the work area is not divided into an infinite number of cells, so there is no need to increase the storage area of ​​the control unit. In addition, the coordinates of the external corners are used for calculations in the control unit. The number of external corners that appear on the outer shell of the work area is not so large. Calculations based on a small number of external corners do not burden the control unit.

[0023] The autonomously controlled brush cutter located anywhere within the work area can then be quickly and unmanned to its destination, allowing the operator to focus on other tasks during the move. Therefore, according to claim 1, an autonomously controlled grass cutter is provided that can reduce the size and cost of the control unit and reduce the burden on the operator.

[0024] In the invention according to claim 2, as in claim 1, the work area is not divided into an infinite number of cells, so there is no need to increase the storage area of ​​the control unit. In addition, the coordinates of the external corners are used for calculations in the control unit. The number of external corners that appear on the outer shell of the work area is not so large. Calculations based on a small number of external corners do not burden the control unit.

[0025] The autonomously controlled brush cutter located anywhere within the work area can then be quickly and unmanned to its destination, allowing the operator to focus on other tasks during the move. Therefore, according to claim 2, an autonomously controlled grass cutter is provided that can reduce the size and cost of the control unit and reduce the burden on the operator.

[0026] Furthermore, while claim 1 connects the aircraft to the destination, etc., in a straight line at the first selection point and the second selection point, claim 2 always connects the aircraft to the destination in a straight line. As a result, claim 2 allows the aircraft to reach the destination via a route that is shorter than claim 1.

[0027] In the invention according to claim 3, the autonomously controlled grass cutter travels autonomously within a work circle of any size set by the operator. In other words, it is possible to mow the grass within the work circle in a concentrated manner. Since there is no need to divide the work circle into countless cells, there is no need to increase the memory area of ​​the control unit. This concentrated mowing operation is also not required by the operator. Therefore, according to claim 2, an autonomously controlled grass cutter can be provided that can reduce the size and cost of the control unit and reduce the burden on the operator. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a front view of an autonomously controlled grass cutter according to the present invention. [Figure 2] FIG. 2 is a right side view of the autonomously controlled brush cutter according to the present invention. [Figure 3] 1 is a plan view of the configuration of an autonomously controlled grass cutter according to the present invention; [Figure 4] FIG. 1( a ) is a diagram for explaining the different travel directions of the mower, and FIG. 1( b ) is a diagram for explaining forward and reverse travel. [Figure 5] (a) is a diagram of the lawnmower approaching the boundary wire, and (b) is a diagram of the lawnmower moving away from it. [Figure 6] FIG. 10 is a diagram (plan view) for explaining a working mode. [Figure 7] FIG. 10 is a diagram illustrating a feedback mode. [Figure 8] FIG. 10 is a diagram illustrating leftover grass. [Figure 9] FIG. 10 is a diagram illustrating the creation of an area map. [Figure 10] 10(a) and 10(b) are diagrams illustrating the straight-ahead mode. [Figure 11] Next, a diagram illustrating the straight ahead mode. [Figure 12] Next, a diagram illustrating the straight ahead mode. [Figure 13] Next, a diagram illustrating the straight ahead mode. [Figure 14] 10A and 10B are diagrams illustrating a straight-ahead mode in a modified example. [Figure 15] FIG. 1 is a diagram illustrating a work circle and concentrated cutting. [Figure 16] 1(a) and 1(b) are diagrams illustrating a conventional autonomously controlled grass cutter. [Figure 17] 1(a) and 1(b) are diagrams illustrating a conventional autonomously controlled grass cutter. DETAILED DESCRIPTION OF THE INVENTION

[0029] An embodiment of the present invention will be described below with reference to the accompanying drawings. Note that front, rear, left and right are defined based on the center of the fuselage 18 shown in FIG. [Example]

[0030] [Autonomous controlled grass cutter] As shown in Figure 1, an autonomously controlled grass cutter (hereinafter referred to as the grass cutter) 10 has a front wheel 11, a left rear wheel 12L, and a right rear wheel 12R. The grass cutter 10 also has a horizontally long rectangular opening 14 in the center of the front surface of a cover 13. A V-shaped part (Figure 3, reference numeral 36) is disposed at the back of this opening 14. As shown in FIG. 2, a cutter housing 16 is provided between the front wheel 11 and the rear wheel axle 15 .

[0031] [Control unit and sensors] When the cover 13 is removed, the machine body 18 shown in FIG. 3 appears. As shown in Figure 3, in a grass cutter 10 having a body 18, a rotating cutting blade 19, a front wheel 11 positioned in front of the cutting blade 19, and rear wheels 12L, 12R positioned behind the cutting blade 19, the grass cutter 10 is equipped with a left wire sensor 21L and a right wire sensor 21R positioned on the front wheel 11 side of the cutting blade 19.

[0032] The cutting blade 19 is driven by a cutting blade motor 24. This cutting blade motor 24 is supplied with power from a battery 25, and the rotation speed and forward, stop, and reverse rotation are controlled by a control unit 27 via a driver 26. When the cutting blade motor 24 is in an overload state, it is controlled to rotate in the reverse direction.

[0033] The front wheels 11 are driven by a front wheel motor 28. This front wheel motor 28 is supplied with power from a battery 25, and the rotation speed and forward, stop, and reverse rotation are controlled by a control unit 27 via a driver 29. The front wheels 11 are steerable wheels and are steered by a steering motor 31. The steering motor 31 is supplied with power from a battery 25 and is controlled by a control unit 27 via a driver 32 to travel straight ahead, steer left, or steer right.

[0034] The left rear wheel 12L is driven by a left rear wheel motor 33L. The left rear wheel motor 33L is supplied with power from a battery 25, and the rotation speed and forward, stop, and reverse rotation are controlled by a control unit 27 via a driver 34L. Similarly, the right rear wheel 12R is driven by a right rear wheel motor 33R. The right rear wheel motor 33R is supplied with power from a battery 25, and the rotation speed and forward, stop, and reverse rotation are controlled by the control unit 27 via a driver 34R.

[0035] Many conventional brush cutters are front-wheel drive or rear-wheel drive vehicles to reduce costs. If the drive wheels lift off the ground for some reason (for example, if the cutter housing surrounding the cutting blade runs over a bump), the mower becomes unable to move. In this case, the grass cutter owner must run over to the mower and move it away from the bump.

[0036] In contrast, the brush cutter 10 of the present invention shown in Figure 3 is an all-wheel drive vehicle, so as long as the front wheels 11 are in contact with the ground, even if the rear wheels 12L and 12R are lifted off the ground, the brush cutter can release itself and continue to run. As a result, the burden on the manager is significantly reduced.

[0037] Furthermore, the brush cutter 10 of the present invention may have two front wheels 11, one on the left and one on the right, but in the embodiment, one wheel is used. With one wheel, the number of front wheel motors 28, drivers 29, steering motors 31, and drivers 32 can be halved, which reduces costs.

[0038] For convenience of drawing, the battery 25 and the control unit 27 are drawn outside the airframe 18, but they are actually disposed on the airframe 18. A V-shaped part 36 is disposed at the front of the body 18, and a charging terminal 37 is provided on this V-shaped part 36. The battery 25 is charged externally via the charging terminal 37.

[0039] The control unit 27 also receives detection signals of the boundary wires (FIG. 4(b), reference numeral 38) from the left wire sensor 21L and the right wire sensor 21R. The control unit 27 also includes an antenna 39 for receiving a signal transmitted from a terminal 50 handled by an operator. The antenna 39 may be built into the control unit 27.

[0040] Additionally, the brush cutter 10 is equipped with a direction sensor 41 and a GPS sensor 42.

[0041] Also provided are a rotation speed sensor 43L that measures the rotation speed of the left rear wheel motor 33L and transmits the rotation speed information to the control unit 27, and a rotation speed sensor 43R that measures the rotation speed of the right rear wheel motor 33R and transmits the rotation speed information to the control unit 27. Either the rotation speed sensor 43L or the rotation speed sensor 43R may be omitted.

[0042] The control unit 27 can calculate the travel distance of the brush cutter 10 from the circumference of the left rear wheel 12L multiplied by the number of rotations. The same applies to the right rear wheel 12R. By providing both rotation speed sensor 43L and rotation speed sensor 43R, the rotation speeds can be averaged. Also, by monitoring the difference between rotation speed sensor 43L and rotation speed sensor 43R, sensor abnormalities can be quickly detected.

[0043] As shown in FIG. 4(a), the mower 10 moves forward as indicated by arrow (1), turns left as indicated by arrow (2), turns right as indicated by arrow (3), and moves backward as indicated by arrow (4). As shown in Figure 4(b), when the mower 10 moving forward as indicated by arrow (1) approaches the boundary wire 38 and both the left wire sensor 21L and the right wire sensor 21R detect the electromagnetic field emitted by the boundary wire 38, the control unit (Figure 3, reference numeral 27) causes the mower 10 to move backward as indicated by arrow (4). After moving the mower 10 forward for a certain distance or for a certain time, the mower 10 is turned to the left or right, and after turning for a certain distance or for a certain time, the mower 10 switches to normal operation.

[0044] As shown in Fig. 5(a), when only the left wire sensor 21L detects the boundary wire 38, the control unit (Fig. 3, reference numeral 27) turns the brush cutter 10 to the right as indicated by the arrow (3), as shown in Fig. 5(b). After turning for a certain distance or for a certain period of time, the brush cutter 10 switches to normal operation.

[0045] Although not shown in the drawings, when only the right wire sensor 21R detects the boundary wire 38, the brush cutter 10 is turned left, and after turning for a certain distance or a certain time, it is switched to normal operation.

[0046] [Device] Using the terminal 50 shown in Fig. 3, the operator can select, for example, "work mode," "return mode," "straight ahead mode," or "straight ahead concentrated mowing mode." The control unit (Fig. 3, reference numeral 27) controls the operation of the brush cutter 10 based on the selected mode. The terminal 50 is preferably a wireless mobile terminal, but may also be a wired fixed terminal. The terminal 50 is preferably a tablet terminal that allows display and operation on the same screen.

[0047] Work Mode When the work mode is selected, the mower 10 starts from the charging station 52 shown in FIG. 6 and mows the work area 54 surrounded by the boundary wire 38 while traveling autonomously.

[0048] The control unit may be set to start work at 8:00 a.m. and finish work at 5:00 p.m., so that the robot automatically departs at 8:00 a.m. and returns automatically at 5:00 p.m.

[0049] [Return Mode] When the remaining battery voltage drops to a predetermined value, the feedback mode is automatically implemented. In addition, the return mode will be automatically activated when work ends at 5:00 p.m. Furthermore, the worker can forcibly implement the return mode by operating the terminal (FIG. 3, reference numeral 50).

[0050] When the return mode is selected, as shown in Figure 7, the brush cutter 10 located somewhere in the work area 54 returns to the charging station 52 along the boundary wire 38. At the charging station 52, the battery (Figure 3, reference numeral 25) is automatically charged, preparing for the start of work the next morning.

[0051] [Necessity of concentrated mowing] When the above-described working mode and return mode are repeated, there is a certain probability that uncut grass 55 will occur, as shown in Figure 8. In other words, because the brush cutter 10 cuts grass evenly and evenly within the working area 54, uncut grass 55 will inevitably occur if there is a high density of thick-stemmed grass.

[0052] The worker periodically visually inspects the condition of the work area 54 (particularly the degree of mowing). During this inspection, the worker discovers an uncut area 55. The worker then takes action by directing the brush cutter 10 to the uncut area 55 and having it mow the uncut area 55 intensively.

[0053] However, as shown in Figure 8, the working area 54 is not a simple rectangle, but has a complex shape, so it is not easy to move the grass cutter 10 straight up to the uncut area 55. Therefore, in the present invention, the control described below is carried out by a control unit (FIG. 3, reference numeral 27).

[0054] [Create an area map] When the operator issues a command to create an area map using the terminal, the brush cutter 10 starts from the charging station 52 and makes a clockwise turn along the boundary wire 38, as shown in Fig. 9. During this time, the control unit performs the following operations. (1a) The travel distance of the brush cutter 10 is calculated from the rotation speed of the motor and the circumference of the rear wheels. (1b) When a right turn is recognized based on the direction of the steering by the direction sensor or the steering motor, the value is set to "0", and when a left turn is recognized, the value is set to "1". "0" corresponds to an inside corner, and "1" corresponds to an outside corner. (1c) The coordinate information of "0" and "1" is obtained using the GPS sensor.

[0055] (1d) The outer shell 56 of the work area 54 is created using the coordinates of "0", "1", and the movement distance. This completes the creation of the area map. The area map (outer shell 56) is displayed on the terminal.

[0056] Although the outer shell wire 56 is different from the boundary wire 38 in the strict sense, they are similar in terms of the macroscopic scale, and for the sake of convenience, they are considered to be in the same position.

[0057] (1e) In this example, there are four protruding corners (points). The control unit stores the coordinates of point A (xa, ya), point B (xb, yb), point C (xc, yc), and point D (xd, yd).

[0058] [Area map update] When the shape (topography) of the work area 54 changes, an area map is created and updated. In other words, if the shape (topography) of the work area 54 does not change, there is no need to create the area map again.

[0059] [Destination setting] The worker sets the location of the uncut grass (Figure 8, reference numeral 55) on the terminal. Specifically, the worker taps the area map displayed on the terminal with his / her finger. Then, as shown in FIG. 10(a), the destination 58 is displayed and the coordinates (x0, y0) of the destination 58 are determined.

[0060] [Straight ahead mode] Once the destination is set, the control unit automatically switches to the straight ahead mode. Alternatively, the operator may select the "straight ahead mode" without automatically switching to the straight ahead mode. When the straight ahead mode is selected or shifted to, the control unit performs the following process.

[0061] (2a) As shown in FIG. 10(a), calculate the distance from the destination 58 to the corner (points A to D). For example, ((x0-xa) 2 +(y0-ya) 2 ) 0.5 The distance La can be obtained by the formula = La. The same applies to distances Lb to Ld.

[0062] (2b) Organize the distances. In this example, La <Ld<Lb<Lc。 That is, of the multiple outside corners, point A is selected as the outside corner closest to destination 58, point D is selected as the outside corner next closest to destination 58, point B is selected as the outside corner next closest to destination 58, and point C is selected as the outside corner next closest to destination 58.

[0063] (2c) In FIG. 10(b), a point (1) is assigned to the coordinates that are a predetermined distance into the work area 54 from point A, which is the corner closest to the destination 58.

[0064] [Specified distance] If the positioning accuracy of the GPS sensor is 3 m, the error in the position coordinates will be about 3 m. If the specified distance is too small, this error will cause false detection of the boundary wire. Setting the specified distance to 3 m prevents false detection. However, if no problems occur during test runs, etc., the specified distance can be reduced to about 2 m. Therefore, the predetermined distance is preferably about 2 m or 3 m.

[0065] (2d) Point (2) is assigned to the coordinates that are a predetermined distance into the work area 54 from point D, which is the next closest corner to the destination 58. (2e) A point (3) is assigned to the coordinates that are a predetermined distance into the work area 54 from point B, which is the next closest corner to the destination 58. (2f) A point (4) is assigned to the coordinates that are a predetermined distance into the work area 54 from point C, which is the next closest corner to the destination 58.

[0066] (2g) As shown in Figure 11, a straight line 61 connects the mower 10 at a certain position to the destination 58. This straight line 61 intersects with the outer shell line 56. The straight line 61 that intersects with the outer shell line 56 is determined not to reach the destination 58. For convenience, an X is marked on the straight line 61 (same below).

[0067] (2h) Similarly, connect the grass cutter 10 to point (1) with a straight line 62, and connect the grass cutter 10 to point (2) with a straight line 63. Both straight lines 62 and 63 intersect with the outer shell line 56, forming an "X". (2i) A straight line 64 connects the mower 10 to the point (3), and a straight line 65 connects the mower 10 to the point (4). Neither line intersects with the outer shell line 56.

[0068] (2j) Of the points (3) and (4) that do not intersect with the outer shell line 56, the point (3) with the smaller number is selected and designated as the "first selected point." (2k) The control unit moves the grass cutter 10 straight to the "first selected point" (i.e., point (3)).

[0069] (2l) As shown in FIG. 12, the grass cutter 10 has reached the "first selected point" (point (3)). When it is recognized that it has reached the point, a straight line 66 is drawn between the grass cutter 10 and the destination 58. This straight line 66 intersects with the boundary wire 38. The intersection is marked with an "X". Similarly, a straight line 67 connects the mower 10 to point (1), and a straight line 68 connects the mower 10 to point (2). Neither line intersects with the outer shell line 56.

[0070] (2n) Of the points (1) and (2) that do not intersect with the outer shell line 56, the point (1) with the smaller number is selected and designated as the "second selected point." (2O) The control unit moves the brush cutter 10 straight to the "second selected point" (i.e., point (1)).

[0071] (2p) When the grass cutter 10 reaches the "second selection point" (point (1)), a straight line 69 connects the grass cutter 10 and the destination 58. This straight line 69 does not intersect with the outer shell line 56. (2q) Then, the control unit controls the grass cutter 10 to go straight to the destination 58. The grass cutter 10 reaches the destination 58 (including the vicinity thereof). This completes the straight ahead mode.

[0072] As shown in FIG. 13, in a work area 54 with a complex shape, the straight ahead mode allows the grass cutter 10 at a certain location to move to a destination along a route that is close to the shortest distance. The uses of "straight ahead mode" are as follows: (Application 1) When you want to quickly move the working brush cutter 10 to a specified destination 58. After moving, you can select "Working Mode" to switch to normal autonomous mowing. (Use 2) When you want to quickly move the grass cutter 10 at the charging station 52 to a specified destination 58. After moving, you can select "Working Mode" to switch to normal autonomous mowing. (Use 3) When you want to quickly retrieve the lawnmower 10 because you have doubts about the movement of the lawnmower 10 while it is in use.

[0073] [Example of change] Consider the case where the destination 58 shown in FIG. 11 is at a different location than that shown in FIG. Assume that a destination 58 is set as shown in FIG. 14(a). Even in this case, straight lines 61 to 64 are used to connect the destination 58 and points (1), (2), (3), (4), etc. from the brush cutter 10, and those of these straight lines 61 to 64 that intersect with the outer shell line 56 (those marked with an x) are excluded, and if the destination 58 is included in this exclusion, the first selected point (3) with the smallest number is selected from those that are not excluded ((3) and (4)), and the direction sensor 41 is used to point the brush cutter 10 toward the first selected point (3). The brush cutter 10 is still driven straight ahead.

[0074] However, in this modified example, when the control unit shifts to the straight ahead mode, it always connects the brush cutter 10 and the destination 58 with a straight line 61 and checks whether this straight line 61 intersects with the outer shell line 56 or not. In this example, when the brush cutter 10 reaches point B before reaching the first selected point (3), the straight line 61 no longer intersects with the outer shell line 56, as shown by the dashed line. The control unit then causes the brush cutter 10 to head from point B to the destination 65 .

[0075] As a result, the mower 10 can reach the destination 58 via the route shown in Figure 14(b). This route is shorter than the route shown in Figure 13, and is therefore more preferable.

[0076] Depending on the location of the destination 58, the straight line 61 may not intersect with the outer shell line 56 while the grass cutter 10 is moving from the first selected point (3) to the second selected point (1). At this point, the control unit directs the grass cutter 10 to the destination 58.

[0077] [Straight-line concentrated mowing mode] When the operator selects the straight-line concentrated mowing mode, the "straight-line mode" described above is followed by the "concentrated mowing operation" described below.

[0078] [Intensive mowing] During the sequential inspection, the worker can know the approximate size (length and width dimensions) and approximate location of the uncut grass (FIG. 8, reference numeral 55). Therefore, the worker uses the terminal to set a work circle 71 shown in Fig. 15(a). The center of the work circle 71 is the destination 58 set in advance by the worker.

[0079] Since the position is approximate, it is recommended that the diameter of the work circle 71 be slightly larger than the size of the uncut grass. The diameter of the work circle 71 may also be selected from, for example, 10 m, 20 m, and 40 m.

[0080] The brush cutter 10, which has been moving straight to the destination 58 in the straight mode, ends operation in the straight mode when it reaches an imaginary circle 72 with a diameter of 4 m that surrounds the destination 58 (point P1). From point P1, the system shifts to autonomous control. After the shift, the grass cutter 10 travels autonomously. During autonomous travel, when the grass cutter 10 moves away from the destination 58 by the radius of the work circle 71 (near point P2), the control unit causes the grass cutter 10 to turn toward the destination 58. During this time, autonomous travel is maintained, and grass cutting is continued.

[0081] Thereafter, as shown in FIG. 15(b), the brush cutter 10 travels autonomously, passing from point P2 near destination 58. During autonomous travel, when the brush cutter 10 moves away from destination 58 by the radius of work circle 71 (near point P3), the control unit causes the brush cutter 10 to turn toward destination 58. Thereafter, the control unit causes the brush cutter 10 to turn near points P4 and P5. As a result, the brush cutter 10 mows intensively within the work circle 71.

[0082] It is important to note here that the positional accuracy of coordinates obtained by a GPS sensor is approximately 3m. Therefore, the center of the work circle 71 (destination 58) may deviate from the center of the uncut grass (FIG. 8, reference numeral 55) by about 3 m. However, even if some grass is left uncut again, the concentrated mowing operation can be performed again, so there is no real harm. Therefore, deviation of the work circle 71 is permissible.

[0083] 9 is also offset by several meters from the boundary wire 38. However, if the brush cutter 10 detects the boundary wire 38, it will not cross this boundary wire 38. Therefore, even if the accuracy of the completed area map is poor, there is no significant harm.

[0084] That is, the present invention is characterized by the ability to implement "straight-line mode" and "straight-line concentrated mowing operation" while accepting the accuracy of the GPS sensor. Currently, various technologies have been proposed to improve the positioning accuracy of GPS sensors, for example by increasing the number of GPS satellites or the number of GPS sensors, but all of these increase costs. In this regard, in the present invention, it is not a problem if the accuracy of the GPS sensor is low, which allows for cost reduction.

[0085] Based on the above detailed description, the present invention can be summarized as follows. As shown in FIG. 3, an autonomously controlled brush cutter 10 is provided with a machine body 18, a swiveling cutting blade 19, a front wheel 11 disposed in front of the cutting blade 19, rear wheels 12L, 12R disposed behind the cutting blade 19, motors 33L, 33R that drive the rear wheels 12L, 12R, a battery 25 that supplies power to the motors 33L, 33R, wire sensors 21L, 21R that detect an area wire (FIG. 6, reference numeral 38) that encloses a work area, and a control unit 27 that controls the rotation of the rear wheels 12L, 12R and the steering of the front wheel 11, and the following applies to the autonomously controlled brush cutter 10: The autonomously controlled grass cutter 10 further includes a GPS sensor 42 that acquires the position coordinates of the machine body 18, and a direction sensor 41 that acquires direction information of the machine body 18. The control unit 27 is capable of operating in a work mode (Figure 6) in which the machine 18 moves autonomously while mowing grass, a return mode (Figure 7) in which the machine 18 returns to the charging station 52 when the remaining voltage of the battery 25 drops to a predetermined level, and a straight-line mode (Figure 13) in which the machine 18 moves straight to a destination 58 set by the operator within the work area.

[0086] As shown in FIG. 9, in the straight ahead mode, the control unit 27 acquires the coordinates of a plurality of points (points A to D) of the corners on the outer shell line 56 of the work area by the GPS sensor . Then, as shown in FIG. 10, the distance from each corner to the destination 58 is calculated based on the coordinates of these corners and the coordinates of the destination 58, the corner closest to the destination 58 is selected, and point (1) is assigned to the coordinates located a predetermined distance from this corner into the work area, and the next corner closest to the destination is selected, and point (2) is assigned to the coordinates located a predetermined distance from this corner into the work area, and points (1), (2), (3), (4), etc. are assigned in this manner.

[0087] Then, as shown in FIG. 11, lines 61 to 64 are drawn from the machine body 18 (brush cutter 10) to the destination 58 and points (1), (2), (3), (4), etc., and those of these lines 61 to 64 that intersect with the outer shell line 56 (those marked with an x ​​in FIG. 11) are excluded. If the destination 58 is included in the excluded lines, the first selected point (3) with the smallest number is selected from those that are not excluded ((3) and (4)), and the machine body 18 is directed straight toward the first selected point (3) using the direction sensor 41.

[0088] Then, as shown in FIG. 12, when the machine 18 (brush cutter 10) reaches the first selection point (3), lines 66-68 are drawn from the machine 18 to the destination 58 and points (1), (2), (3), (4), etc., and any of these lines that intersect with the outer shell line 56 are excluded. If the destination 58 is included in the excluded lines, the second selection point (1) with the smallest number is selected from the remaining lines, and the direction sensor 41 is used to point the machine 18 toward the second selection point (1) and cause it to travel straight ahead. This process is repeated until the line connecting the machine 18 and the destination 58 no longer intersects with the outer shell line 56, and when the line 69 connecting the machine 18 and the destination 58 no longer intersects with the outer shell line 56, the machine 18 travels straight ahead to the destination 58.

[0089] Preferably, the intensive mowing operation described below is added to the straight ahead mode. That is, the control unit 27 can perform concentrated mowing operation in addition to the work mode, the return mode, and the straight mode.

[0090] As shown in Figure 15(a), in the concentrated mowing operation, the operator sets a work circle 71 of any diameter centered on the destination 58, and the control unit 27 causes the machine 18 to travel autonomously after it arrives at the destination 58 (point P1), and when the machine 18 has moved away from the destination 58 by the radius of the work circle 71 (point P2), causes the machine 18 to travel autonomously while turning toward the destination 58.

[0091] Thereafter, as shown in Figure 15(b), the aircraft 18 is repeatedly turned toward the destination 58 when it moves away from the destination 58 by the radius of the work circle 71 (P3, P4, P5).

[0092] The mower of the present invention may also be applied to a lawn mower. In addition, in the embodiment, the front wheels 11 are provided with the front wheel motors 28, but the front wheel motors 28 may be omitted and the front wheels 11 may be driven wheels. [Industrial Applicability]

[0093] The present invention is suitable for an autonomously controlled grass cutter that performs grass cutting work unmanned. [Explanation of symbols]

[0094] 10...autonomously controlled grass cutter (grass cutter), 11...front wheel, 12L, 12R...rear wheel, 18...machine, 19...cutting blade, 21L, 21R...wire sensor, 25...battery, 27...control unit, 33L, 33R...motor (rear wheel motor), 38...area wire, 41...orientation sensor, 42...GPS sensor, 52...charging station, 54...working area, 56...outer shell wire, 58...destination, 71...working circle.

Claims

1. An autonomously controlled grass cutter that travels autonomously and includes a machine body having a swiveling blade, front wheels disposed in front of the blade, rear wheels disposed behind the blade, a motor that drives the rear wheels, a battery that supplies power to the motor, a wire sensor that detects an area wire that encloses a work area, and a control unit that controls the rotation of the rear wheels and the steering of the front wheels, The autonomously controlled brush cutter further includes a GPS sensor that acquires the position coordinates of the machine body, and a direction sensor that acquires the direction information of the machine body, the control unit is capable of operating a work mode in which the machine performs grass cutting while autonomously traveling, a return mode in which the machine returns to a charging station when the remaining voltage of the battery drops to a predetermined level, and a straight-line mode in which the machine travels straight to a destination set by an operator within the work area, In the straight-ahead mode, the control unit acquires the coordinates of a plurality of external corners on the outer hull line of the work area using the GPS sensor, calculates the distance from each external corner to the destination based on the coordinates of these external corners and the coordinates of the destination, selects the external corner closest to the destination and assigns point (1) to the coordinates located a predetermined distance from this external corner into the work area, selects the next external corner closest to the destination and assigns point (2) to the coordinates located a predetermined distance from this external corner into the work area, and assigns points (1), (2), (3), (4), etc. in this manner, and then connects the destination and points (1), (2), (3), (4), etc. from the aircraft with straight lines, excluding those lines that intersect with the outer hull line, and if the destination is included in this exclusion, assigns points (1), (2), (3), (4), etc. from the non-excluded lines. an autonomously controlled brush cutter, which selects a first selection point with the lowest number, directs the machine to travel straight toward the first selection point using the direction sensor, and when the machine reaches the first selection point, connects the machine to the destination and points (1), (2), (3), (4), ... with straight lines, excluding those lines that intersect with the outer shell line, and when the destination is included in the excluded lines, selects a second selection point with the lowest number from those that are not excluded, directs the machine to travel straight toward the second selection point using the direction sensor, and repeats this process until the straight line connecting the machine to the destination no longer intersects with the outer shell line, and when the straight line connecting the machine to the destination does not intersect with the outer shell line, controls the machine to travel straight toward the destination.

2. An autonomously controlled grass cutter that travels autonomously and includes a machine body having a swiveling blade, front wheels disposed in front of the blade, rear wheels disposed behind the blade, a motor that drives the rear wheels, a battery that supplies power to the motor, a wire sensor that detects an area wire that encloses a work area, and a control unit that controls the rotation of the rear wheels and the steering of the front wheels, The autonomously controlled brush cutter further includes a GPS sensor that acquires the position coordinates of the machine body, and a direction sensor that acquires the direction information of the machine body, the control unit is capable of operating a work mode in which the machine performs grass cutting while autonomously traveling, a return mode in which the machine returns to a charging station when the remaining voltage of the battery drops to a predetermined level, and a straight-line mode in which the machine travels straight to a destination set by an operator within the work area, In the straight-ahead mode, the control unit acquires the coordinates of a plurality of external corners on the outer shell line of the work area using the GPS sensor, calculates the distance from each external corner to the destination based on the coordinates of these external corners and the coordinates of the destination, selects the external corner closest to the destination and assigns point (1) to the coordinates located a predetermined distance from this external corner into the work area, selects the external corner next closest to the destination and assigns point (2) to the coordinates located a predetermined distance from this external corner into the work area, and assigns points (1), (2), (3), (4), ... in this manner, next connects the destination and points (1), (2), (3), (4), ... from the aircraft with straight lines, excludes those lines that intersect with the outer shell line, and when the destination is included in these excluded lines, selects a first selected point with the smallest number from those that are not excluded, and directs the aircraft toward the first selected point using the orientation sensor and moves it straight an autonomously controlled brush cutter, characterized in that while traveling in a straight line, the machine always connects the machine to the destination in a straight line, and if this line no longer intersects the outer hull line, the machine is made to travel in a straight line toward the destination; if the line connecting the machine to the destination remains intersecting the outer hull line, when the machine reaches the first selected point, a straight line is connected from the machine to points (1), (2), (3), (4) ..., a second selected point with the smallest number is selected, and the machine is directed toward the second selected point using the orientation sensor to travel in a straight line; while traveling in a straight line, the machine always connects the machine to the destination in a straight line, and if this line no longer intersects the outer hull line, the machine is made to travel in a straight line toward the destination; and if the line connecting the machine to the destination remains intersecting the outer hull line, the machine is made to continue traveling in a straight line toward the second selected point;

3. The autonomously controlled grass cutter according to claim 1 or 2, The control unit is capable of performing concentrated mowing operation in addition to the work mode, the return mode, and the straight mode, In the concentrated mowing operation, the operator sets a work circle of any diameter centered on the destination, and the control unit causes the vehicle to drive autonomously after arriving at the destination, and when the vehicle moves away from the destination by the radius of the work circle, causes the vehicle to drive autonomously while turning toward the destination, and thereafter, when the vehicle moves away from the destination by the radius of the work circle, causes the vehicle to turn toward the destination, repeatedly performing this process.

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