Lawn mower

Abstract

To provide a mower capable of suppressing an overload on a blade motor.SOLUTION: A mower includes a mower body, an information acquisition unit 50, a load prediction unit 52, a route setting unit 53, and a drive motor control unit 54. The mower body has a drive motor that drives a moving mechanism and a blade motor that drives a blade for mowing grass. The information acquisition unit 50 acquires information on a growth status of grass in a mowing target area. The load prediction unit 52 predicts a load on the blade motor when mowing grass on the basis of information on the growth status. The route setting unit 53 sets a travel route on the basis of the predicted load. The drive motor control unit 54 controls the drive of the drive motor so that the mower body travels along the set travel route.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a lawn mower.

Background Art

[0002] Patent Document 1 discloses a self-propelled lawn mower that reduces the load on the motor for the cutting blade by mowing while meandering, and describes switching to a method of mowing while meandering when the load on the motor for the cutting blade increases.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a self-propelled lawn mower, if it is constantly meandering, the mowing efficiency will decrease. On the other hand, when switching the operation mode according to the load on the motor for the cutting blade as in the lawn mower described in Patent Document 1, since it switches to the meandering mode after the load on the motor for the cutting blade becomes large, the motor for the cutting blade may become overloaded.

[0005] In consideration of the above facts, an object of the present invention is to obtain a lawn mower that can suppress an overload on the motor for the cutting blade.

Means for Solving the Problems

[0006] The grass trimmer according to claim 1 includes: a grass trimmer body having a drive motor for driving a moving mechanism and a cutting blade motor for driving a cutting blade for cutting grass; an information acquisition unit for acquiring information on the growth status of grass in a grass-cutting target area; a load prediction unit for predicting the load on the cutting blade motor when cutting grass based on the information on the growth status acquired by the information acquisition unit; a path setting unit for setting a travel path based on the load predicted by the load prediction unit; and a drive motor control unit for driving and controlling the drive motor so that the grass trimmer body travels along the travel path set by the path setting unit. The route setting unit sets the travel route so that the cumulative value of the load does not exceed a predetermined threshold. .

[0007] In the grass trimmer according to claim 1, information regarding the growth status of grass in the area to be mowed is acquired, the load on the cutting blade motor when mowing is predicted based on the acquired information, and the travel path is set based on the predicted load. Therefore, by considering the load on the cutting blade motor in advance and setting a travel path that does not result in an overload on the cutting blade motor, it is possible to suppress an overload on the cutting blade motor.

[0009] Claim 1 In the grass trimmer according to the present invention as described above, the path setting unit sets the travel path so that the cumulative load value does not exceed a predetermined threshold, thereby suppressing fatigue failure of the motor for the cutting blade.

[0010] Claim 2 The grass trimmer according to the present invention described herein is The lawnmower body includes a drive motor for driving a moving mechanism and a cutting blade motor for driving a cutting blade for cutting grass; an information acquisition unit for acquiring information on the growth status of grass in the area to be mowed; a load prediction unit for predicting the load on the cutting blade motor when mowing the grass based on the information on the growth status acquired by the information acquisition unit; a path setting unit for setting a travel path based on the load predicted by the load prediction unit; and a drive motor control unit for controlling the drive motor so that the lawnmower body travels along the travel path set by the path setting unit. The route setting unit sets the travel route so that the maximum value of the load does not exceed a predetermined threshold.

[0011] Claim 2 In the grass trimmer according to the present invention described above, Information regarding the growth status of grass in the area to be mowed is acquired, and based on the acquired information, the load on the cutting blade motor when mowing is predicted, and the travel path is set based on the predicted load. Therefore, by considering the load on the cutting blade motor in advance and setting a travel path that does not result in an overload on the cutting blade motor, it is possible to suppress an overload on the cutting blade motor. Furthermore, in the grass mower according to the present invention as described in claim 2, The route setting unit sets the travel path so that the maximum load does not exceed a predetermined threshold, thereby suppressing damage to the cutting blade motor.

[0012] Claim 3 The grass trimmer according to the present invention described herein is The lawnmower body includes a drive motor for driving a moving mechanism and a cutting blade motor for driving a cutting blade for cutting grass; an information acquisition unit for acquiring information on the growth status of grass in the area to be mowed; a load prediction unit for predicting the load on the cutting blade motor when mowing the grass based on the information on the growth status acquired by the information acquisition unit; a path setting unit for setting a travel path based on the load predicted by the load prediction unit; and a drive motor control unit for controlling the drive motor so that the lawnmower body travels along the travel path set by the path setting unit. The route setting unit sets an initial travel route for the area to be mowed and sets the travel route by correcting the initial travel route based on the load predicted by the load prediction unit.

[0013] Claim 3 In the grass trimmer according to the present invention described above, Information regarding the growth status of grass in the area to be mowed is acquired, and based on the acquired information, the load on the cutting blade motor when mowing is predicted, and the travel path is set based on the predicted load. Therefore, by considering the load on the cutting blade motor in advance and setting a travel path that does not result in an overload on the cutting blade motor, it is possible to suppress an overload on the cutting blade motor. Furthermore, in the grass mower according to the present invention as described in claim 3, The path setting unit sets an initial travel path for the area to be mowed, and the load prediction unit corrects the initial travel path based on the predicted load. Therefore, the initial travel path can be corrected so that the load on the cutting blade motor does not become excessive, thereby suppressing overload on the cutting blade motor. [Effects of the Invention]

[0014] As described above, the grass trimmer according to the present invention has the excellent effect of being able to suppress overload on the motor for the cutting blade. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic perspective view illustrating the configuration of a lawnmower according to the first embodiment of the present invention. [Figure 2] This is a side cross-sectional view showing a partially broken state of a grass trimmer according to the first embodiment of the present invention, as viewed from the side. [Figure 3] This is a block diagram showing the hardware configuration of a lawnmower according to the first embodiment of the present invention. [Figure 4] This is a block diagram showing the functional configuration of a grass trimmer according to the first embodiment of the present invention. [Figure 5] This is a flowchart showing a series of processes for a lawnmower according to the first embodiment of the present invention. [Figure 6] This is a flowchart showing a series of processes for a lawnmower according to a second embodiment of the present invention. [Modes for carrying out the invention]

[0016] (First Embodiment) The lawn mower 10 according to the first embodiment of the present invention will be described with reference to the drawings. In the figures, the arrows UP, FR, and RH indicate the upper side in the vertical direction, the front side in the front-rear direction, and the right side in the left-right direction of the lawn mower 10, respectively. Also, since the lawn mower 10 is configured to be movable in both directions in the front-rear direction, the forward direction and the traveling direction do not necessarily coincide.

[0017] As shown in FIGS. 1 and 2, the lawn mower 10 of the present embodiment mainly includes a lawn mower body 12, a cutting blade unit 14, and a control unit 16.

[0018] (Lawn mower body 12) The lawn mower body 12 is formed in a substantially rectangular parallelepiped shape with the lower side open, and a crawler portion 18 as a moving mechanism is provided on the lawn mower body 12. The crawler portions 18 are provided on both the left and right sides at the front end portion and both the left and right sides at the rear end portion of the lawn mower body 12.

[0019] Each crawler portion 18 includes a rubber crawler 18A, a drive wheel 18B, a first idler wheel 18C, and a second idler wheel 18D. The rubber crawler 18A is formed in an endless belt shape and is wound around the drive wheel 18B, the first idler wheel 18C, and the second idler wheel 18D.

[0020] The drive wheel 18B is connected to a drive motor 35 (see FIG. 3) disposed inside the lawn mower body 12 via a rotating shaft not shown. The drive motor 35 is configured to be supplied with electric power from a battery not shown. By supplying electric power to operate the drive motor 35, the drive wheel 18B rotates and the rubber crawler 18A moves in a circulating manner in one direction.

[0021] The first idler wheel 18C is positioned forward and below the drive wheel 18B and is rotatably mounted on a rotating shaft (not shown) that extends in the left-right direction. The first idler wheel 18C rotates in accordance with the movement of the rubber crawler 18A. The second idler wheel 18D is positioned behind the first idler wheel 18C and is rotatably mounted on a rotating shaft (not shown) that extends in the left-right direction. The second idler wheel 18D rotates in accordance with the movement of the rubber crawler 18A.

[0022] Here, the drive motors 35 are independently provided for each of the four crawler sections 18, and by controlling the four drive motors 35, the grass trimmer 10 can be moved in any direction. Note that in Figure 3, for the sake of explanation, the four drive motors 35 are shown together.

[0023] A cover 20 is provided on the front of the brush cutter body 12. The cover 20 is a substantially flat plate-shaped member with the front-to-back direction as the thickness direction, and extends in both the vertical and horizontal directions. The lower end of the cover 20 is located below the lower end of the brush cutter body 12, and the cover 20 narrows the gap between the brush cutter body 12 and the ground. This cover 20 prevents foreign objects such as stones from entering the cutting blade unit 14, which will be described later.

[0024] In this embodiment, as an example, the cover 20 is provided only on the front of the lawnmower body 12, but this is not limited to this. For example, similar covers 20 may also be provided on the rear and sides of the lawnmower body 12. In addition, members to prevent foreign objects from entering may be provided on both sides of the lawnmower body 12, similar to the cover 20.

[0025] (Cutting blade unit 14) As shown in Figure 2, a cutting blade unit 14 is provided inside the main body 12 of the grass trimmer. The cutting blade unit 14 consists of a rotating member 22, a cutting blade 24, a rotating shaft 26, and a motor 28 for the cutting blade.

[0026] The rotating member 22 is positioned near the lower opening 12A of the brush cutter body 12, with its vertical direction being the thickness direction of the plate. The rotating member 22 is also fixed to a rotating shaft 26, which will be described later, and is configured to rotate together with the rotating shaft 26 with respect to the brush cutter body 12.

[0027] The rotating member 22 is provided with a plurality of cutting blades 24. The cutting blades 24 are attached to the outer peripheral end of the rotating member 22, and in this embodiment, as an example, four cutting blades 24 are provided at equal intervals along the circumferential direction of the rotating member 22.

[0028] Each cutting blade 24 is formed from a thin metal member with the vertical direction being the thickness direction, and is configured to cut grass.

[0029] The rotating shaft 26 is located in the central part of the brush cutter body 12 and extends vertically, with a rotating member 22 attached to its lower end. The upper end of the rotating shaft 26 is connected to the cutting blade motor 28.

[0030] The cutting blade motor 28 is mounted on the top of the grass trimmer body 12 and is driven by power supplied from a battery (not shown) located in the grass trimmer body 12. The cutting blade motor 28 also has an output shaft (not shown), and this output shaft and the rotating shaft 26 are connected via a gear or pulley (not shown). Therefore, when the cutting blade motor 28 is driven, rotational force is transmitted to the rotating member 22 via the rotating shaft 26, causing the rotating member 22 to rotate in one direction around the rotating shaft 26.

[0031] As shown in Figures 1 and 2, the control unit 16 is located on the upper surface of the lawnmower body 12 and has a roughly rectangular parallelepiped housing 16A.

[0032] A GPS (Global Positioning System) device 32 is mounted on the top surface of the housing 16A. The GPS device 32 is a device for measuring the current position of the lawnmower 10 and includes an antenna (not shown) that receives signals from GPS satellites.

[0033] A camera unit 34, which serves as an imaging device, is mounted on the front of the housing 16A. The camera unit 34 is a unit composed of multiple cameras and can capture images of the surrounding environment, including the direction in which the grass trimmer 10 is moving. A controller 36 is also provided in the control unit 16.

[0034] (Hardware configuration of lawnmower 10) Figure 3 is a block diagram showing the hardware configuration of the lawnmower 10. As shown in Figure 3, the controller 36 that makes up the lawnmower 10 includes a CPU (Central Processing Unit: processor) 38, ROM (Read Only Memory) 40, RAM (Random Access Memory) 42, storage 44, communication I / F (communication interface) 46, and input / output I / F (input / output interface) 48. Each component is connected to each other so as to be able to communicate with each other via a bus 49.

[0035] The CPU 38 is the central processing unit, which executes various programs and controls various components. Specifically, the CPU 38 reads programs from the ROM 40 or storage 44 and executes them using the RAM 42 as a working area. The CPU 38 also controls the above-mentioned components and performs various calculations according to the programs recorded in the ROM 40 or storage 44.

[0036] ROM 40 stores various programs and data. RAM 42 is a non-temporary recording medium that temporarily stores programs or data as a working area. Storage 44 is composed of an HDD (Hard Disk Drive) or SSD (Solid State Drive) and is a non-temporary recording medium that stores various programs, including the operating system, and various data. In this embodiment, storage 44 stores the automatic driving program and various data for the lawnmower 10.

[0037] Communication I / F46 is an interface for the lawnmower 10 to communicate with other devices, and standards such as CAN (Controller Area Network), Ethernet (registered trademark), LTE (Long Term Evolution), FDDI (Fiber Distributed Data Interface), and Wi-Fi (registered trademark) are used.

[0038] The input / output interface 48 is electrically connected to the GPS device 32, camera unit 34, drive motor 35, and cutting blade motor 28. The controller 36 controls the drive motor 35 based on the surrounding image detected by the camera unit 34 and information such as the current position of the grass trimmer 10 acquired by the GPS device 32, thereby making the grass trimmer 10 move automatically.

[0039] (Functional configuration of the lawnmower 10) The lawnmower 10 implements various functions using the hardware resources described above. The functional configuration implemented by the lawnmower 10 will be explained with reference to Figure 4.

[0040] As shown in Figure 4, the lawnmower 10 is configured as follows: an information acquisition unit 50, a load prediction unit 52, a path setting unit 53, a drive motor control unit 54, and a cutting blade motor control unit 56. Each of these functional configurations is realized by the CPU 38 reading and executing a program stored in the ROM 40 or storage 44.

[0041] The information acquisition unit 50 acquires image information of the direction of travel of the lawnmower 10 captured by the camera unit 34, and also acquires information such as the current position of the lawnmower 10 acquired by the GPS device 32. In addition, the information acquisition unit 50 acquires information regarding the growth status of grass in the area to be mowed.

[0042] Here, we will explain how to obtain information on the growth status of grass. As an example of how to obtain this information, for each type of grass growing in the area to be mowed, data is obtained in advance by measuring how much the grass grows in a predetermined period. Then, the area to be mowed is divided into multiple sections, and the degree of sunlight exposure is set for each section. Here, the degree of sunlight exposure is set according to the direction the section faces (south-facing, north-facing, etc.). Note that the degree of sunlight exposure is considered higher the more south-facing the section is.

[0043] Then, based on the above data and the degree of sunlight, an equation is created to indicate the grass growth status, and the grass growth status is derived based on that equation. For example, the following equation (1) can be used as the equation. P = H (mm / t) × T (t) × K ... (1) In equation (1) above, P is an index representing the growth status of the grass, H is the amount of grass height growth per unit time, T is time, and K is a weighting coefficient according to the degree of sunlight. Note that the weighting coefficient according to the degree of sunlight increases as the degree of sunlight increases.

[0044] The methods for obtaining information on the growth status of grass are not limited to those described above. For example, aerial images of the area to be mowed can be obtained by flying a drone equipped with a camera beforehand, and grass can be detected from the image information of the aerial images, and the height of the grass can be calculated by image processing.

[0045] Specifically, aerial images are analyzed to obtain orthomosaic image data, which is 3D image data accurately displaying the position and size of the subject, and RGB image data, which is color image data containing color information. The coordinate position information of the RGB image data and the orthomosaic image data converted from the RGB image data are associated. Then, using a known method, the locations where grass is growing are detected from the RGB image data, and the height of the grass at the detected locations is detected in the orthomosaic image data.

[0046] Furthermore, AI (artificial intelligence) technology may be used as a method for obtaining information on the growth status of grass. Specifically, the growth status of grass may be derived using a pre-trained model that has been machine-learned using learning information that includes image information of the area to be mowed, environmental information such as sunlight hours and temperature, and the height of the grass in the area to be mowed.

[0047] Furthermore, a technique using a multispectral camera may be used to obtain information on the growth status of grass. This is a known technique that allows for the investigation of plant growth status by observing sunlight, artificial light, and the light reflected from grass, trees, etc. For example, the color of light differs between grasses in good growth condition and grasses in poor growth condition, so the growth status of grass can be investigated.

[0048] The load prediction unit 52 predicts the load on the cutting blade motor 28 when mowing grass, based on the information on the grass growth status obtained by the information acquisition unit 50. Specifically, the load prediction unit 52 derives and stores a table in which the relationship between grass height and the output value of the drive motor 35 is set in advance. The load prediction unit 52 refers to the above table and obtains the output of the drive motor 35 corresponding to the grass height as the load on the cutting blade motor 28 when mowing grass of that height.

[0049] The route setting unit 53 sets a travel route based on the load predicted by the load prediction unit 52 and stores it in the storage 44, for example. In this embodiment, the route setting unit 53 sets a travel route such that the cumulative value of the load does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2. Here, the predetermined threshold A1 is set to a value smaller than the cumulative value of the load at which the cutting blade motor 28 experiences fatigue failure when the cutting blade 24 actually cuts grass. The predetermined threshold A2 is set to a value smaller than the load at which the cutting blade motor 28 is damaged when the cutting blade 24 actually cuts grass.

[0050] The drive motor control unit 54 controls the output of the drive motor 35, which is located inside the lawnmower body 12. Specifically, the drive motor control unit 54 controls the drive motor 35 so that the lawnmower 10 travels along the travel path by referring to the travel path, map data, images captured by the camera unit 34, and the current position of the lawnmower 10 acquired by the GPD device 32, which are stored in the storage 44. Furthermore, if an object approaching the lawnmower 10 is detected in the images captured by the camera unit 34, the drive motor control unit 54 can control the drive motor 35 to temporarily stop the lawnmower 10.

[0051] When the drive motor control unit 54 starts the movement of the grass trimmer 10, the cutting blade motor control unit 56 drives and controls the rotation speed, rotation speed, and rotation direction of the cutting blade motor 28 based on the rotation speed, rotation speed, and rotation direction of the cutting blade motor 28 that have been set in advance. In addition, the cutting blade motor control unit 56 can control the cutting blade motor 28 to temporarily stop the rotation of the cutting blade 24 when an object approaching the grass trimmer 10 is detected in the image captured by the camera unit 34, or when the cutting blade motor 28 is overloaded.

[0052] (Operation and effects of the first embodiment) Next, the operation and effects of the first embodiment will be described.

[0053] Figure 5 is a flowchart showing an example of a series of processes performed by the lawnmower 10. This series of processes by the lawnmower 10 is executed by the CPU 38 reading a program from the ROM 40 or storage 44 and loading it into the RAM 42.

[0054] As shown in Figure 5, in step S10, the CPU 38 sets the area to be mowed by the grass cutter 10. Specifically, information indicating the area to be mowed is input via input / output I / F 48 by an input means (not shown) and stored in storage 44.

[0055] Next, in step S11, the CPU 38 acquires information regarding the grass growth status. Specifically, the CPU 38 acquires information regarding the grass growth status using the above formula (1) as described above, through the function of the information acquisition unit 50. At this time, as an example, the time elapsed since the last mowing was performed in the mowing target area stored in the storage 44 is input via the input / output I / F 48 using an input means (not shown).

[0056] Next, in step S12, the CPU 38 predicts the load on the cutting blade motor 28. Specifically, the CPU 38, using the function of the load prediction unit 52, predicts the load on the cutting blade motor 28 when mowing grass, based on the information on the grass growth status acquired by the information acquisition unit 50, as described above.

[0057] Next, in step S13, the CPU 38 sets the travel route. Specifically, the CPU 38 uses the function of the route setting unit 53 to set the travel route so that the cumulative value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2, as described above. At this time, the route setting unit 53 outputs data indicating the location of the location, for example, via the communication I / F 46, if the grass has grown beyond the predetermined threshold A1 or A2 and the location is outside the travel route. As a result, the grass at that location is mowed manually either in advance or after the mowing by the grass cutter 10 is completed, based on the output data.

[0058] Next, in step S14, the CPU 38 starts mowing the grass in the area to be mowed using the grass trimmer 10. Specifically, the CPU 38 controls the drive motor 35 using the functions of the drive motor control unit 54 so that the grass trimmer 10 travels along the travel path as described above.

[0059] Next, in step S15, the CPU 38 determines whether the grass cutting of the target area by the grass cutter 10 has been completed. Specifically, it determines whether the grass cutting is complete by determining whether the grass cutter 10 has completed traveling along the travel path set by the path setting unit 53. If the grass cutting is not completed (step S15; NO), the CPU 38 has the grass cutter 10 continue cutting until the grass cutting is completed. On the other hand, if the grass cutting is completed (step S15; YES), the CPU 38 terminates the series of processes.

[0060] As described above, in the first embodiment of the grass trimmer 10, the grass around the grass trimmer body 12 can be cut by rotating the cutting blade 24 while moving the grass trimmer body 12 with the crawler section 18 which serves as a moving mechanism.

[0061] Furthermore, in the first embodiment, the grass trimmer 10 acquires information regarding the growth status of grass in the area to be mowed, predicts the load on the cutting blade motor 28 when mowing based on the acquired information, and sets the travel path based on the predicted load. Therefore, by considering the load on the cutting blade motor 28 in advance and setting a travel path that does not result in an overload on the cutting blade motor 28, it is possible to suppress an overload on the cutting blade motor 28.

[0062] Furthermore, in the first embodiment, the path setting unit 53 of the grass trimmer 10 sets the travel path so that the cumulative load on the cutting blade motor 28 does not exceed a predetermined threshold A1, thereby suppressing fatigue failure of the cutting blade motor 28.

[0063] Furthermore, in the first embodiment, the path setting unit 53 of the grass trimmer 10 sets the travel path so that the maximum load applied to the cutting blade motor 28 does not exceed a predetermined threshold A2, thereby suppressing damage to the cutting blade motor 28.

[0064] (Second Embodiment) Next, a lawnmower 10-2 (see Figure 1) according to the second embodiment of the present invention will be described. Since the lawnmower 10-2 of the second embodiment has substantially the same configuration as the lawnmower 10 of the first embodiment, the description of the similar parts will be omitted, and only the differences will be described.

[0065] In the first embodiment described above, the path setting unit 53 of the grass trimmer 10 sets the travel path so that the cumulative value of the load predicted in advance by the load prediction unit 52 does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2. However, in the second embodiment, the path setting unit 53 of the grass trimmer 10-2 sets an initial path in advance for the area to be mowed. The path setting unit 53 then readjusts the travel path by correcting the initial travel path based on the load applied to the cutting blade motor 28 predicted by the load prediction unit 52.

[0066] Specifically, the route setting unit 53 corrects the initial travel route so that the cumulative value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2.

[0067] (Operation and effects of the second embodiment) Next, the operation and effects of the second embodiment will be described.

[0068] Figure 6 is a flowchart showing an example of a series of processes performed by the lawnmower 10-2. This series of processes by the lawnmower 10-2 is executed by the CPU 38 reading a program from the ROM 40 or storage 44 and loading it into the RAM 42.

[0069] As shown in Figure 6, in step S20, the CPU 38 sets the area to be mowed by the grass cutter 10. Specifically, information indicating the area to be mowed is input via an input / output I / F 48 by an input means (not shown) and stored in the storage 44.

[0070] Next, in step S21, the CPU 38 sets an initial travel path for the area to be mowed. Specifically, the CPU 38 sets the initial travel path to cover the entire area to be mowed using the function of the path setting unit 53.

[0071] Next, in step S22, the CPU 38 acquires information regarding the growth status of the grass in the same manner as in the first embodiment described above, and in step S23, it predicts the load on the cutting blade motor 28.

[0072] Next, the CPU 38 detects the cumulative load on the cutting blade motor 28 when traveling along the set travel path and the maximum load on the cutting blade motor 28 when traveling along the set travel path, based on the load on the cutting blade motor 28 predicted in step S24.

[0073] Next, the CPU 38 determines whether the cumulative load on the cutting blade motor 28 when traveling along the travel path set in step S25 exceeds a predetermined threshold A1, or whether the maximum load on the cutting blade motor 28 when traveling along the set travel path exceeds a predetermined threshold A2. If step 25 is denied (step S25; NO), the CPU 38 sets the initial travel path as the travel path using the function of the route setting unit 53 in step S26.

[0074] On the other hand, if step S25 is affirmed (step S25; YES), the CPU 38 corrects the initial travel route in step S27. Specifically, the CPU 38 resets the travel route by correcting the initial travel route using the function of the route setting unit 53 so that the cumulative value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2.

[0075] Next, in step S28, the CPU 38 starts mowing the area to be mowed using the lawnmower 10-2. Then, in step S29, the CPU 38 determines whether or not the mowing of the area to be mowed by the lawnmower 10-2 is complete. If the mowing is not complete (step S29; NO), the CPU 38 has the lawnmower 10-2 continue mowing until the mowing is complete. On the other hand, if the mowing is complete (step S29; YES), the CPU 38 terminates the series of processes.

[0076] As described above, in the second embodiment of the grass trimmer 10-2, the path setting unit 53 sets an initial travel path for the grass trimming target area and corrects the initial travel path based on the load predicted by the load prediction unit 52. Therefore, the initial travel path can be corrected so that the load on the cutting blade motor 28 does not become excessive, thereby suppressing overload on the cutting blade motor 28.

[0077] Although the above-described embodiments of the grass trimmers 10 and 10-2 have been explained, it goes without saying that the present invention can be implemented in various forms without departing from the spirit of the invention. In the above embodiments, the load on the cutting blade motor 28 was predicted only according to the height of the grass, but the present invention is not limited thereto. For example, the diameter of the grass stem may be estimated, and the load on the cutting blade motor 28 may be predicted considering the estimated stem diameter.

[0078] Specifically, one method is to add a stem diameter estimation unit to the functional configuration of the lawnmowers 10 and 10-2. The stem diameter estimation unit identifies the type of grass detected on the planned route that the lawnmower body 12 will travel, based on the image information acquired by the information acquisition unit 50. For example, it identifies the type of grass by referring to a pre-stored database of grasses and comparing it with the image information. The stem diameter estimation unit then estimates the stem diameter from the identified type of grass. At this time, the stem diameter estimation unit may also estimate the stem diameter by considering the grass height calculated by the information acquisition unit 50.

[0079] Furthermore, in the embodiment described above, the route setting unit 53 sets a travel route such that the cumulative value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A1, and the maximum value of the load does not exceed a predetermined threshold A2. However, the present invention is not limited thereto. For example, the route setting unit 53 may set a travel route such that the cumulative value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A1, or it may set a travel route such that the maximum value of the load predicted by the load prediction unit 52 does not exceed a predetermined threshold A2.

[0080] Furthermore, although a GPS device 32 was used as the satellite positioning system in the embodiments described above, the present invention is not limited thereto. For example, known technologies such as GNSS (Global Navigation Satellite System) and QZSS (Quasi-Zenith Satellite System) can be used.

[0081] Furthermore, although the crawler section 18 in the above-described embodiment is formed of a rubber crawler 18A that is a roughly right-angled triangular column, the present invention is not limited to this. For example, it may be elliptical or circular, and can be modified as appropriate.

[0082] Furthermore, although the lawnmowers 10 and 10-2 in the above-described embodiments are four-wheel drive, the present invention is not limited to this and may also be two-wheel drive.

[0083] Furthermore, although the crawler section 18 was used as the drive unit in the above-described embodiment, the present invention is not limited thereto. The drive unit may be, for example, a wheel. Also, the drive unit of the present invention is not limited to four, and may have a structure with one drive unit on the left side and one on the right side.

[0084] Furthermore, the processing that the CPU 38 reads and executes in the above-described embodiment may be executed by various processors other than the CPU 38. Examples of such processors include PLDs (Programmable Logic Devices) such as FPGAs (Field-Programmable Gate Arrays) whose circuit configuration can be changed after manufacturing, and dedicated electrical circuits that are processors with circuit configurations specifically designed to execute particular processing, such as ASICs (Application Spec Integrated Circuits). In addition, the above processing may be executed by one of these various processors, or by a combination of two or more processors of the same or different types, for example, by multiple FPGAs, or by a combination of a CPU and an FPGA. More specifically, the hardware structure of these various processors is an electrical circuit that combines circuit elements such as semiconductor elements.

[0085] Furthermore, although the above-described embodiment involves storing various data in the storage 44, the system is not limited to this. For example, non-temporary recording media such as CDs (Compact Disks), DVDs (Digital Versatile Disks), and USB (Universal Serial Bus) memory may be used as storage units. In this case, various programs and data will be stored in these recording media.

[0086] Furthermore, the processing flow described in the above-mentioned embodiments is merely an example, and unnecessary steps may be deleted, new steps added, or the processing order rearranged, as long as it does not deviate from the main purpose. [Explanation of symbols]

[0087] 10 Lawn Mower 10-2 Lawn Mower 12. Lawn mower body 18. Crawler section (movement mechanism) 28 Motor for cutting blades 35 Drive motor 50 Information Acquisition Department 52 Load prediction unit 53 Route setting section 54 Drive motor control unit

Claims

1. A grass trimmer body having a drive motor for driving the moving mechanism and a motor for driving the cutting blade for cutting grass, An information acquisition unit that acquires information on the growth status of grass in the area to be mowed, A load prediction unit predicts the load applied to the motor for the cutting blade when the grass is cut, based on the information on the growth status obtained by the information acquisition unit. A route setting unit sets a travel route based on the load predicted by the load prediction unit, A drive motor control unit controls the drive motor so that the lawnmower body travels along the travel path set by the route setting unit, Includes, The aforementioned route setting unit is a lawnmower that sets the travel route so that the cumulative value of the load does not exceed a predetermined threshold.

2. A grass trimmer body having a drive motor for driving the moving mechanism and a motor for driving the cutting blade for cutting grass, An information acquisition unit that acquires information on the growth status of grass in the area to be mowed, A load prediction unit predicts the load applied to the motor for the cutting blade when the grass is cut, based on the information on the growth status obtained by the information acquisition unit. A route setting unit sets a travel route based on the load predicted by the load prediction unit, A drive motor control unit controls the drive motor so that the lawnmower body travels along the travel path set by the route setting unit, Includes, The aforementioned route setting unit is a lawnmower that sets the travel route so that the maximum value of the load does not exceed a predetermined threshold.

3. A grass trimmer body having a drive motor for driving the moving mechanism and a motor for driving the cutting blade for cutting grass, An information acquisition unit that acquires information on the growth status of grass in the area to be mowed, A load prediction unit predicts the load applied to the motor for the cutting blade when the grass is cut, based on the information on the growth status obtained by the information acquisition unit. A route setting unit sets a travel route based on the load predicted by the load prediction unit, A drive motor control unit controls the drive motor so that the lawnmower body travels along the travel path set by the route setting unit, Includes, The aforementioned path setting unit sets an initial travel path for the area to be mowed, and the mower sets the travel path by correcting the initial travel path based on the load predicted by the load prediction unit.

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