Lawn mower

Abstract

A mower includes a mower body having a cutting blade section that cuts grass, a first position estimation section that estimates a self position of the mower body using a satellite positioning system, a second position estimation section that estimates the self position of the mower body using a sensor section provided to the mower body, a detection section that detects a place covered by grass in a travel path set in advance, and an automatic travel control section that causes the mower body to travel on the travel path with reference to the self position estimated by the first position estimation section, and switches to causing the mower body to travel with reference to the self position estimated by the second position estimation section at the place covered by grass detected by the detection section.

Description

TECHNICAL FIELD

[0001] The present application relates to a mower. BACKGROUND

[0002] In Japanese Patent Application Laid-Open No. 9-128045, it is disclosed that, in a mower which automatically travels, a path of the mower is generated based on measurement data measured by a Global Positioning Satellite (GPS) while the mower is manually operated in advance in a work target area. SUMMARY

[0003] In the mower described in Japanese Patent Application Laid-Open No. 9-128045, in a case where, for example, a travel path is covered with trees or the like when mowing is performed by automatic travel, in measurement using the GPS, the accuracy of self-position estimation can possibly decrease.

[0004] The present application provides a mower which can suppress a decrease in the accuracy of self-position estimation when automatically traveling.

[0005] The mower of the present application comprises:

[0006] a mower body which has a cutter portion for mowing grass;

[0007] a first position estimation portion which estimates a self-position of the mower body using a satellite positioning system;

[0008] a second position estimation portion which estimates the self-position of the mower body using a sensor portion provided to the mower body;

[0009] a detection portion which detects a place covered with grass and trees in a travel path set in advance; and

[0010] an automatic travel control portion which causes the mower body to travel on the travel path with reference to the self-position estimated by the first position estimation portion, and switches to cause the mower body to travel with reference to the self-position estimated by the second position estimation portion at the place covered with the grass and trees detected by the detection portion.

[0011] In the lawn mower of the present application, a cutting blade section for cutting grass is provided to the lawn mower main body. Thus, the grass can be cut by the cutting blade section. In addition, the lawn mower of the present application is provided with a first position estimation section for estimating the self position of the lawn mower main body using a satellite positioning system, and a second position estimation section for estimating the self position of the lawn mower main body using a sensor section provided to the lawn mower main body. Thus, the self position can be estimated by the first position estimation section and the second position estimation section. In addition, in the lawn mower of the present application, a detection section for detecting a place covered by grass and trees in a travel path set in advance is provided. Thus, the place covered by grass and trees can be detected by the detection section.

[0012] In addition, in the lawn mower of the present application, in particular, the automatic travel control section causes the lawn mower main body to travel while referring to the self position estimated by the first position estimation section on the travel path, and switches to causing the lawn mower main body to travel while referring to the self position estimated by the second position estimation section at the place covered by grass and trees detected by the detection section. Thus, at the place where it is considered difficult to estimate the self position by the satellite positioning system, the estimation of the self position can be performed using the sensor section instead of the satellite positioning system, so that the decrease in the accuracy of the estimation of the self position can be suppressed.

[0013] In the lawn mower of the present application,

[0014] The detection section acquires RGB image data having color information and orthographic image data corresponding to a photographing region of the RGB image data and including point group data,

[0015] The detection section determines the grass and trees based on the color information in the RGB image data, and determines the height of the grass and trees based on height information of the point group data in the orthographic image data, thereby detecting the place covered by the grass and trees.

[0016] According to the lawn mower of the present application, the position of the grass and trees can be determined by the RGB image data, and the height of the grass and trees can be determined by the orthographic image data. Thus, the height of the grass and trees on the travel path can be determined based on the orthographic image data and the RGB image data.

[0017] In the lawn mower of the present application, the detection section detects the place covered by the grass and trees by comparing first image data including an image of the travel path and acquired at a first period with second image data acquired at a second period different from the first period.

[0018] The mower according to the present application detects the place covered with grass by comparing the first image data and the second image data taken at different times, respectively. Therefore, the place covered with grass on the travel road can be determined based on the first image data and the second image data.

[0019] In the mower according to the present application,

[0020] The above first time period is a mowing time period,

[0021] The above second time period is a time period in which grass is less than the mowing time period.

[0022] The mower according to the present application can take an image covered with grass and an image not covered with grass at a predetermined place on the travel road. Therefore, the place covered with grass can be easily determined by comparing the images.

[0023] In the mower according to the present application, the above sensor portion is constituted by one or more sensors selected from a plurality of sensors including a distance measuring sensor, a camera, a gyro sensor, a magnetic sensor, an acceleration sensor, and a radar sensor.

[0024] The mower according to the present application can take information about the position of the mower body by one or more sensors selected from a plurality of sensors including a distance measuring sensor, a camera, a gyro sensor, a magnetic sensor, an acceleration sensor, and a radar sensor. Thus, the self position of the mower body can be estimated from the information about the position of the mower body.

[0025] As described above, the mower according to the present application has an excellent effect of being able to suppress the decrease in the accuracy of the self position estimation at the time of automatic travel. BRIEF DESCRIPTION OF DRAWINGS

[0026] The features, advantages, and technical and industrial significance of exemplary embodiments of the application will be described in the following non-limiting detailed description with reference to the accompanying drawings, in which like numerals refer to like elements throughout the figures. The figures are presented

[0027] Figure 1 is a perspective view schematically illustrating the structure of a mower according to an embodiment of the present application;

[0028] Figure 2 is a perspective view of the mower of Figure 1 from a lower side;

[0029] Figure 3 is a perspective view schematically illustrating the structure of a cutter portion of the mower of Figure 1 ; and

[0030] Figure 4is a block diagram showing a hardware structure of a mower that shows an embodiment of the present application;

[0031] Figure 5 is a block diagram showing a functional structure of a mower that shows an embodiment of the present application;

[0032] Figure 6 is a plan view schematically showing an entire water culture field region including a travel road at a mowing period;

[0033] Figure 7 is a side view schematically showing a travel road at a mowing period;

[0034] Figure 8 is a flowchart showing a series of processes of a mower that shows an embodiment of the present application;

[0035] Figure 9 is a side view schematically showing a travel road at a winter season. DETAILED DESCRIPTION

[0036] A mower 10 of an embodiment of the present application is described with reference to the drawings. Note that arrows UP shown in each drawing indicate an upper side in a vehicle up-down direction. Arrows FR indicate a front side in a vehicle front-rear direction. Further, arrows LH indicate a left side in a vehicle width direction. Arrows RH indicate a right side in the vehicle width direction. The up-down direction and the front-rear direction in the following description mean up-down in the vehicle up-down direction and front-rear in the vehicle front-rear direction, respectively. Further, the left-right direction means left-right in the vehicle width direction.

[0037] Structure of the mower 10

[0038] The mower 10 of the first embodiment is a self-propelled mower. The mower 10 mows, for example, a ridge or a field of a farmland or the like. The mower 10 as a mower main body has, for example, as shown in Figure 1 a main body 12, a crawler 14 as a drive unit, a motor controller 16, a battery device 18, a control device 20, a drive motor 22, a camera unit 24, a GPS device 26, a sensor unit 27, an outer cover unit 28, and a cutter unit 30.

[0039] As shown in Figure 1 and Figure 2As shown, the main body 12 is formed of a substantially rectangular plate. Various devices are placed on the upper surface of the main body 12. In addition, a bottom cover 12A is provided to the main body 12. The bottom cover 12A covers the inner side in the vehicle width direction of the four crawler belts 14 described later. The bottom cover 12A is formed of a plate. The bottom cover 12A is provided in a substantially rectangular shape extending downward from both end portions of the main body 12 in the vehicle width direction at positions corresponding to the four crawler belts 14. In this embodiment, the main body 12 and the bottom cover 12A are integrally formed as an example, but can be separately formed.

[0040] In addition, in the main body 12, a cutter cover 13 is provided between the two bottom covers 12A provided on the left and right sides. The cutter cover 13 covers the cutter 36 of the cutter portion 30 described later. The cutter cover 13 is formed of a plate, and both ends in the vehicle front-rear direction are connected to the bottom covers 12A of the two crawler belts 14. The main body 12, the bottom cover 12A, and the cutter cover 13 are composed of a metal material such as steel or aluminum, a fiber-reinforced plastic material, or the like as an example.

[0041] The cutter cover 13 has a central portion 13A, two inclined portions 13B, and an upper portion 13C. The central portion 13A is formed in a rectangular shape. The central portion 13A is provided to protrude outward in the vehicle width direction than the bottom cover 12A. The two inclined portions 13B are provided at both ends in the vehicle front-rear direction of the central portion 13A. The inclined portions 13B extend obliquely from both ends in the vehicle front-rear direction of the central portion 13A toward the bottom cover 12A. The upper portion 13C is formed in a substantially trapezoidal shape. The four sides of the upper portion 13C are connected to the main body 12, the central portion 13A, and the two inclined portions 13B, respectively. In this embodiment, the cutter cover 13 and the main body 12 and the bottom cover 12A are separately formed as an example with respect to the cutter cover 13. However, they can be integrally formed. The cutter cover 13 prevents the insertion of foreign matter from the side of the mower 10, that is, the left and right sides, to the cutter 36, and prevents the scattered grass from flying to the side of the mower 10.

[0042] The crawler portions 14 are provided on both left and right sides in the front-rear direction. The mower 10 of the present embodiment has four crawler portions 14. Each crawler portion 14 has a rotating portion 14A and a crawler 14B. The rotating portion 14A is formed of a substantially right-angled triangular column. The rotating portion 14A rotates about an axis in the vehicle width direction. The crawler 14B is a member of rubber that covers the outer circumferential surface about the axis of the rotating portion 14A. The crawler 14B is formed in a band shape. The crawler 14B has protrusions and depressions (not shown) formed on the outer surface thereof. With the protrusions and depressions, the crawler 14B is configured to maintain the running property even in a case where the state of the running surface on which the mower 10 runs is unstable. The axis (not shown) of the rotating portion 14A is linked to the motor shaft (not shown) of the drive motor 22. The axis of the rotating portion 14A is rotated by the drive motor 22. In the present embodiment, the two crawler portions 14 on the front and rear sides on the left side in the vehicle width direction are referred to as left crawler portions 14L, and the two crawler portions 14 on the front and rear sides on the right side in the vehicle width direction are referred to as right crawler portions 14R.

[0043] The motor controllers 16 drive control the drive motors 22 and the cutter motors 32 described later. As described later, the mower 10 of the present embodiment has four drive motors 22 and two cutter motors 32. Therefore, the mower 10 of the present embodiment has, as an example, a total of six motor controllers 16A to 16F, i.e., four motor controllers 16A to 16D that drive control the four drive motors 22, respectively, and two motor controllers 16E and 16F that drive control the two cutter motors 32, respectively.

[0044] The motor controllers 16A to 16D that drive control the drive motors 22 are electrically connected to the drive motors 22 and the control device 20 (see Figure 4 ). The motor controllers 16A to 16D control the drive of the rotating portions 14A, i.e., the crawler portions 14, linked to the drive motors 22. The motor controllers 16E and 16F that drive control the cutter motors 32 are electrically connected to the cutter motors 32 and the control device 20 (see Figure 4 ). The motor controllers 16E and 16F drive control the cutters 36 described later linked to the cutter motors 32.

[0045] The battery device 18 is a device that becomes a driving source of the driving motor 22. The battery device 18 is constituted by a rechargeable direct-current power supply having a rated voltage of 18 V and a rated capacity of 6.0 Ah, for example. The battery device 18 is constituted by a secondary battery such as a lithium-ion secondary battery or a nickel-hydrogen battery, for example. The battery device 18 can also employ a capacitor such as an electric double layer capacitor. In the mower 10 of the present embodiment, the battery device 18 is provided with four, for example. The four battery devices 18 supply electric power to the electronic devices mounted on the mower 10, such as the driving motor 22, the cutter motor 32, and the like.

[0046] The control device 20 is a device that controls the driving of the entire mower 10. The control device 20 is disposed on the upper side inside the outer cover portion 28. The control device 20 will be described in detail later.

[0047] The driving motor 22 is provided with four in the mower 10 of the present embodiment. The driving motor 22 is constituted by a DC brushless motor, for example. The four driving motors 22 are connected to the four track portions 14, respectively, and are driven by commands from the motor controllers 16A to 16D, respectively.

[0048] The camera portion 24 is a camera that can take pictures of the surroundings of the mower 10. The camera portion 24 is provided on the front side and the rear side of the upper outer surface of the outer cover portion 28 in the mower 10 of the present embodiment. The camera portions 24 provided on the front side and the rear side each have a 3D (three-dimensional) camera 24A and a Raspberry Pi camera 24B.

[0049] The GPS device 26 has an antenna not shown. The antenna receives a radio signal from a GPS satellite not shown. The GPS device 26 can measure the current position of the mower 10. The GPS device 26 is disposed on the upper side of the control device 20 and is fixed to the outer cover portion 28. The satellite positioning system is constituted by the GPS satellite and the GPS device 26 described above.

[0050] The sensor portion 27 has a three-axis acceleration sensor. The sensor portion 27 outputs the gravitational acceleration in the left-right direction (horizontal direction: x direction), the front-rear direction (horizontal direction: y direction), and the up-down direction (vertical direction: z direction) of the mower 10. In addition, the sensor portion 27 has a gyro sensor that detects the rotation, i.e., the angular velocity, of the mower 10.

[0051] The outer cover portion 28 is formed in a box shape that is open on the lower side. The outer cover portion 28 is a case that covers the main body portion 12 from above.

[0052] The cutter portion 30 has a configuration for mowing grass. Specifically, as shown in FIG. 1, the cutter portion 30 is provided with a cutter 31 and a cutter motor 32. Figure 3As shown, the cutter portion 30 is provided with a rectangular plate-shaped base portion 31 disposed on the upper surface of the main body portion 12. The base portion 31 has a height adjustment configuration (omitted from the drawing) that enables height adjustment in the vertical direction with respect to the main body portion 12. The height adjustment configuration can be either manual or automatic, for example. The height adjustment configuration can use a publicly known configuration.

[0053] The cutter motor 32 is disposed on the upper surface of the base portion 31 with a predetermined interval in the lateral direction. In the present embodiment, the cutter motor 32 is composed of a DC brushless motor as an example.

[0054] The two cutter motors 32 each have a motor shaft 34 that passes through a through-hole (omitted from the drawing) of the base portion 31. A cutter 36 is rotatably fixed to the lower end of each of the two motor shafts 34.

[0055] The cutter 36 has a circular plate portion 37 that is formed in a circular plate shape and is rotatably fixed to the motor shaft 34, and four cutter tips 38 that are fixed in a rectangular shape so as to protrude in four directions from the outer periphery of the circular plate portion 37. The left and right cutters 36 are disposed with a slight positional difference in the vertical direction (height direction) so as to avoid interference between the cutter tips 38. The grass is cut by the cutters 36 being rotationally driven by the cutter motors 32.

[0056] In the present embodiment, the base portion 31 is adjusted in height in the vertical direction by the height adjustment configuration described above. By this adjustment, the height position of the cutter 36 can also be adjusted. In the present embodiment, the height adjustment is performed so that the cutter tip 38 is located at a height of 50 mm from the ground as an example. In addition, the cutter tip 38 can be adjusted in height to a plurality of heights such as 80 mm, 100 mm, in addition to the height of 50 mm from the ground as an example. Thus, the grass can be cut at a plurality of heights.

[0057] In addition, in the present embodiment, the control device 20 controls the travel of the mower 10 based on data acquired by the camera portion 24, the GPS device 26, and the sensor portion 27, and a pre-set travel path stored in the storage device 20D described later.

[0058] Hardware structure of the mower 10

[0059] Next, the control device 20 will be described in detail. As shown in FIG. 2, the control device 20 is composed of a CPU 20A, a ROM 20B, a RAM 20C, and a storage device 20D. Figure 4As shown, the control device 20 mounted on the mower 10 is configured to include a central processing unit (CPU) (processor) 20A, which is an example of a processor, a read only memory (ROM) 20B, a random access memory (RAM) 20C, a storage device 20D, a communication interface (communication I / F) 20E, and an input / output interface (input / output I / F) 20F. The respective structures are connected in a manner capable of communicating with each other via a bus 20G.

[0060] The CPU 20A is a central arithmetic processing unit. The CPU 20A executes various programs, and controls the respective parts. That is, the CPU 20A reads out a program from the ROM 20B or the storage device 20D, and executes the program using the RAM 20C as a work area. The CPU 20A performs the control of the respective structures and various arithmetic processes in accordance with the program recorded in the ROM 20B or the storage device 20D.

[0061] The ROM 20B stores various programs and various data. The RAM 20C temporarily stores a program or data as a work area. The storage device 20D is configured by a hard disk drive (HDD) or a solid state drive (SSD). The storage device 20D stores various programs including an operating system and various data including map data. In addition, the storage device 20D stores a travel route set in advance. In the present embodiment, a program and various data and the like for exerting various functions are stored in the ROM 20B or the storage device 20D.

[0062] The communication I / F 20E is an interface for communication between the mower 10 and a server and other devices not shown. The communication I / F 20E uses, for example, a standard such as Ethernet (registered trademark), LTE, FDDI, Wi-Fi (registered trademark), and the like.

[0063] The input / output I / F 20F is provided as an interface for communication between the control device 20 and the respective devices mounted on the mower 10. Also, the control device 20 is connected in a manner capable of communicating with the respective devices described later via the input / output I / F 20F. In addition, these devices can also be directly connected to the bus 20G.

[0064] In detail, the motor controllers 16A to 16D, the motor controllers 16E, 16F, the camera section 24, the GPS device 26, the sensor section 27, and the like are connected to the input / output I / F 20F.

[0065] The motor controllers 16A to 16D output control signals to the drive motors 22 based on the command signals input from the control device 20. The motor controllers 16A to 16D can control the number of revolutions, the rotation speed, and the rotation direction of the drive motors 22. Also, in the present embodiment, the traveling direction of the mower 10 can be changed by independently controlling the number of revolutions, the rotation speed, and the rotation direction of the motor controllers 16A to 16D by the control device 20 and the motor controllers 16A to 16D, respectively.

[0066] The motor controllers 16E, 16F output control signals to the cutter motors 32 based on the command signals input from the control device 20. The motor controllers 16E, 16F can control the number of revolutions, the rotation speed, and the rotation direction of the cutter motors 32. Also, in the present embodiment, the mowing state of the mower 10 can be changed by independently controlling the number of revolutions, the rotation speed, and the rotation direction of the motor controllers 16E, 16F by the control device 20 and the motor controllers 16E, 16F, respectively.

[0067] The camera section 24 is a camera that captures the surroundings of the mower 10. The captured images of the objects in the surroundings of the mower 10 are temporarily stored in the storage device 20D.

[0068] The GPS device 26 functions as a part of a satellite positioning system. The position information indicating the self-position of the mower 10 that is measured is temporarily stored in the storage device 20D, and the position information of the mower 10 is updated at predetermined intervals.

[0069] The sensor section 27 is a device that detects the gravitational acceleration of the mower 10. The gravitational accelerations in the left-right direction (x direction), the front-rear direction (y direction), and the up-down direction (z direction) output by the sensor section 27 are temporarily stored in the storage device 20D. Also, the data of the gravitational accelerations stored in the storage device 20D is data in a state where noise is removed by applying a predetermined filter to the data of the gravitational accelerations output from the sensor section 27.

[0070] Next, the functional structure of the control device 20 will be described using Figure 5 The control device 20 functions as a collection of the automatic traveling control section 202, the cutter control section 204, the sensing section 206, the first position estimation section 208, and the second position estimation section 210 by the CPU 20A reading out and executing the execution program stored in the ROM 20B.

[0071] The automatic travel control section 202 inputs a control signal to the motor controllers 16A to 16D with reference to the travel road, the map data stored in the storage device 20D, the captured image captured by the camera section 24, and the own position of the mower 10 estimated by the first position estimation section 208 and the second position estimation section 210 described later, and controls the driving motors 22 via the motor controllers 16A to 16D so that the mower 10 travels along the travel road. In addition, the method of causing the mower 10 to travel with reference to the own position estimated by the first position estimation section 208 and the second position estimation section 210 will be described later in detail.

[0072] In addition, in a case where an object approaching the mower 10 is detected in the captured image captured by the camera section 24, the automatic travel control section 202 can control the driving motors 22 via the motor controllers 16A to 16D to temporarily stop the mower 10.

[0073] When the travel of the mower 10 is started by the automatic travel control section 202, the cutter control section 204 inputs the number of revolutions, the rotation speed, and the rotation direction of the cutter motor 32, and the like, which are set in advance, to the motor controllers 16E and 16F. The cutter control section 204 drives and controls the number of revolutions, the rotation speed, and the rotation direction of the cutter motor 32 via the motor controllers 16E and 16F. In addition, in a case where an object approaching the mower 10 is detected in the captured image captured by the camera section 24 or an overload is applied to the cutter motor 32, or the like, the cutter control section 204 can control the cutter motor 32 via the motor controllers 16E and 16F to temporarily stop the rotation of the cutter 36.

[0074] The detection section 206 detects a place covered with grass and trees in the travel road set in advance and stored in the storage device 20D. In the present embodiment, "grass and trees" include leaves growing on branches and grass itself, and the like. In the mower 10 of the present embodiment, the detection section 206 determines a place covered with grass and trees on the basis of RGB image data having color information and orthographic image data, which are images including the travel road set in advance and stored in the storage device 20D. The orthographic image data corresponds to a captured region of the RGB image data and includes point cloud data. In addition, the method of determining a place covered with grass and trees on the travel road by the detection section 206 will be described later in detail.

[0075] The first position estimation section 208 estimates the own position of the mower 10 using a satellite positioning system. Specifically, an antenna (omitted from illustration) of the GPS device 26 receives a radio wave signal from a GPS satellite in the universe space, and outputs to the input-output I / F 20F. The first position estimation section 208 acquires the radio wave signal output from the GPS device 26 via the input-output I / F 20F. The first position estimation section 208 estimates the own position based on the radio wave signal. Specifically, the distance is estimated based on the time difference between the transmission time and the reception time of the radio wave signal. In addition, as for the method of estimating the own position using the GPS device 26, a publicly known technique can be used, and thus detailed explanation thereof is omitted here.

[0076] The second position estimation section 210 estimates the own position of the mower 10 using the sensor section 27. Specifically, the detection data acquired by the sensor section 27, i.e., the gyro sensor and the three-axis acceleration sensor, is output to the input-output I / F 20F. The second position estimation section 210 acquires the detection data output from the gyro sensor and the three-axis acceleration sensor via the input-output I / F 20F. The second position estimation section 210 estimates the own position based on the detection data.

[0077] Specifically, the second position estimation section 210 estimates the orientation, i.e., the moving direction, of the mower 10 based on the angular velocity data output from the gyro sensor. In addition, the second position estimation section 210 estimates the moving distance based on the gravitational acceleration data output from the three-axis acceleration sensor.

[0078] Here, the method of determining the place covered with grass and trees on the travel road by the detecting section 206 is explained. In the present embodiment, the detecting section 206 acquires, as an example, RGB image data and orthographic image (orthographic transformation image) data, the RGB image data being an aerial photograph image, and being a color image having color information. The aerial photograph image is captured by flying a drone equipped with a camera. The orthographic image data is data that accurately shows the position and size of the subject by analyzing the above-described aerial photograph image. In the present embodiment, it is assumed that the orthographic image data has point group data represented by orthogonal coordinates (x, y, z).

[0079] In the present embodiment, as an example, a plurality of aerial photograph images, i.e., RGB image data (image data of the aerial photograph image), are captured by flying a drone equipped with a camera to the place covered with grass and trees on the travel road, and the orthographic image data is acquired by analyzing the RGB image data. Figure 6The area shown is taken from above and from various directions. The data taken is stored in the storage device 20D via the communication I / F 20E. In this embodiment, as an example, the detection unit 206 converts a plurality of aerial images stored in the storage device 20D into orthoimage data including point cloud data using a conversion tool such as Metashape (registered trademark) or the like. In addition, a correspondence is established for the coordinate position information in the RGB image data and the orthoimage data converted from the RGB image data.

[0080] Figure 6 is a plan view schematically showing the entire area of the paddy field 50 including the travel road 60 at the mowing period. Figure 7 is a side view schematically showing the travel road 60 at the mowing period.

[0081] Figure 6 On the orthoimage P, there is overlaid a trajectory 60A indicating the own position of the mower 10 as estimated by the first position estimation unit 208 when the mower 10 travels on the travel road 60. As Figure 6 As shown in the orthoimage P, in the paddy field 50, a dike road W is provided at the boundary of each paddy field area 50A where water is accumulated, which is piled up with soil to prevent water from leaking outwards. Figure 7 As shown in the orthoimage P, grass 70, grass 70A, trees 72, and larger grass 74, etc. other than crops are growing.

[0082] The trees 72 have a trunk 72A extending upward from the ground, and a plurality of branches 72B extending obliquely upward from the outer periphery of the trunk 72A, and leaves 72C extending from the branches 72B. The larger grass 74 is grass having a height higher than that of the grass 70 and the grass 70A. The mower 10 of this embodiment cuts the grass 70 growing in the dike road W as an example, and therefore the travel road 60 for the mower 10 to travel is provided in the dike road W. In addition, the travel road 60 is set in advance based on the RGB image data taken at the winter period which is a period when the grass and trees are less than at the mowing period. In addition, the travel road 60 can be set based on terrain information obtained by, for example, download from an external website, etc.

[0083] In the RGB image (omitted from illustration) corresponding to the orthoimage P shown in Figure 6 In the RGB image (omitted from illustration) corresponding to the orthoimage P shown in

[0084] Based on the orthoimage data, the detection unit 206 detects the height of the vegetation in the area of ​​vegetation identified in the RGB image data as described above. Specifically, the height of the vegetation is detected based on the height information of the point cloud data in the area of ​​vegetation identified in the RGB image data. If the detected height exceeds a predetermined height, the detection unit 206 detects the area exceeding the predetermined height as being covered by vegetation. In this embodiment, the "predetermined height" is set to 1 meter as an example. The detection unit 206 obtains the area covered by vegetation as the vertical and horizontal coordinate positions in the orthoimage P.

[0085] like Figure 6 As shown, trajectory 60A of the lawn mower 10's own position, estimated by first position estimating unit 208 using a satellite positioning system while traveling on travel path 60, includes a first own position 62 indicated by a black line and a second own position 64 indicated by a gray line. First own position 62 is a self-position obtained with higher accuracy than second own position 64.

[0086] As an example, it is assumed that the lawn mower 10 is Figure 6 Start driving from the approximate center of the orthophoto image P shown. In this case, Figure 6 As shown, in the area indicated by the dashed-dotted frame A1 between first path 62A and second path 62B of first self position 62, first self position 62 and second self position 64 are not present, but first path 66A of third self position 66 indicated by the white line is present. This first path 66A is an area where first position estimating unit 208 cannot estimate its own position.

[0087] Specifically, the grass 70A or the grass 70B is covered by leaves 72C of a tree 72 and large grass 74. Figure 7 In the case of grass 70A on the right side and grass 70B on the left side, radio signals from GPS satellites in outer space do not reach the antenna (not shown) of GPS device 26 of lawn mower 10. Thus, the place where radio signals cannot be received on travel path 60 becomes third self position 66.

[0088] In this embodiment, the area corresponding to the third self-position 66 is detected by the detection unit 206 as being covered by vegetation. Therefore, in this embodiment, at the third self-position 66, which is the area detected as covered by vegetation by the detection unit 206, the automatic driving control unit 202 estimates the self-position of the lawn mower 10 using the sensor unit 27 via the second position estimating unit 210, rather than the first position estimating unit 208.

[0089] Specifically, when the mower 10 reaches a place covered with grass and trees from the first own position 62 that is detected by the detection section 206, the automatic travel control section 202 acquires the coordinate position of the own position acquired by the first position estimation section 208 at the first own position 62 adjacent to the place covered with grass and trees. The automatic travel control section 202 causes the mower 10 to travel by referring to the own position calculated by adding the movement distance estimated by the second position estimation section 210 to the coordinate position as a starting point.

[0090] Also, when the mower 10 reaches the first own position 62 from the place covered with grass and trees that is detected by the detection section 206, the automatic travel control section 202 acquires the coordinate position of the own position acquired by the first position estimation section 208 at the first own position 62 adjacent to the place covered with grass and trees. The automatic travel control section 202 causes the mower 10 to travel with reference to the own position estimated by the first position estimation section 208 with respect to the first own position 62 thereafter.

[0091] In the present embodiment, as shown in FIG. 6, in the area indicated by the single-dotted line frame A2 between the first road 62A and the second road 62B of the first own position 62, there are no first own positions 62 and second own positions 64, and there is the second road 66B of the third own position 66 indicated by the white line. In the area indicated by the frame A2, the third road 64C of the second own position 64 exists slightly apart from the first road 64A and the second road 64B between the first road 64A and the second road 64B. Figure 6

[0092] The antenna (omitted from illustration) of the GPS device 26 of the mower 10 does not directly receive the radio signal from the GPS satellite in the universe space but receives the signal bounced by the reflector such as the leaves 72C of the tree 72, and thus a reception delay is generated. Due to this, the third road 64C is generated.

[0093] Therefore, in the present embodiment, the automatic travel control section 202 also causes the mower 10 to travel with reference to the own position estimated by the second position estimation section 210 instead of the first position estimation section 208 at the second own position 64 at which the own position is acquired with lower precision than the first own position 62.

[0094] ​Specifically, the detection unit 206 detects in advance a region in which positioning accuracy decreases when the antenna (omitted from the drawing) of the GPS device 26 receives an electric wave signal from a GPS satellite in the universe. Also, when the mower 10 travels in a region detected by the detection unit 206, that is, a region corresponding to the second own position 64, the automatic travel control unit 202 acquires a coordinate position of the own position acquired by the first position estimation unit 208 at a first own position 62 adjacent to the region. The automatic travel control unit 202 causes the mower 10 to travel by referring to the own position calculated by adding a movement distance estimated by the second position estimation unit 210 to the coordinate position as a starting point.

[0095] As an example, in the travel road 60 shown in FIG. 6, the automatic travel control unit 202 causes the mower 10 to travel in the travel road 60 corresponding to the first road 62A, the second road 62B, the third road 62C, and the fourth road 62D of the first own position 62 with reference to the own position estimated by the first position estimation unit 208. In addition, the automatic travel control unit 202 causes the mower 10 to travel in the first road 64A, the second road 64B, and the fourth road 64D of the second own position 64 and the first road 66A and the second road 66B of the third own position 66 with reference to the own position estimated by the second position estimation unit 210. Figure 6

[0096] Automatic travel control method

[0097] Hereinafter, the flow of a series of processes of the automatic travel control method in the mower 10 will be described using the flowchart shown in FIG. 7. As shown in FIG. 7, in the mower 10 of the first embodiment, first, in step S10, the detection unit 206 detects a region in which a place covered with grass and trees and positioning accuracy decrease in the travel road 60 set in advance, as described above. Figure 8 Figure 8

[0098] Next, in step Sll, the mower 10 starts traveling by the driving control of the driving motor 22 by the automatic travel control unit 202. Also, the mower 10 starts mowing by the driving control of the cutter motor 32 by the cutter control unit 204.

[0099] Next, in step S12, the automatic travel control unit 202 determines whether or not the mower 10 is traveling in a region in which a place covered with grass and trees or positioning accuracy decrease is being detected by the detection unit 206. In a case where the mower 10 is not traveling in a region in which a place covered with grass and trees or positioning accuracy decrease (step S12; No), the process proceeds to step S13. In step S13, the automatic travel control unit 202 causes the mower 10 to travel with reference to the own position estimated by the first position estimation unit 208 using a satellite positioning system.

[0100] ​​​On the other hand, when the lawn mower 10 is traveling in a place covered with grass or in an area where positioning accuracy is reduced in step S12 (step S12; yes), in step S14, the automatic driving control unit 202 drives the lawn mower 10 with reference to its own position estimated by the second position estimating unit 210 using the sensor unit 27.

[0101] Next, in step S15, the automatic driving control unit 202 determines whether mowing is complete. Specifically, the automatic driving control unit 202 determines whether the predetermined driving path 60 has been completed. If mowing is not complete (step S15: No), the CPU 20A proceeds to step S12 and performs the steps thereafter. On the other hand, if mowing is complete (step S15: Yes), the automatic driving control unit 202 stops the lawn mower 10 and ends the operation.

[0102] Functions and effects of implementation methods

[0103] Next, the operation and effects of this embodiment will be described.

[0104] The lawn mower 10 of this embodiment is equipped with a blade unit 30 for mowing grass, so it can be used to mow grass. Furthermore, the lawn mower 10 includes a first position estimating unit 208 that uses a satellite positioning system to estimate the position of the lawn mower 10 itself, and a second position estimating unit 210 that uses a sensor unit 27 provided on the lawn mower 10 to estimate the position of the lawn mower 10 itself. Therefore, the first position estimating unit 208 and the second position estimating unit 210 can be used to estimate the position of the lawn mower 10 itself. Furthermore, the lawn mower 10 includes a detection unit 206 that detects areas covered by grass and trees on a predetermined travel path 60. Therefore, the detection unit 206 can detect areas covered by grass and trees.

[0105] Furthermore, in particular, in the lawn mower 10, the automatic travel control unit 202 controls the lawn mower 10 on the travel path 60 by referring to the self-position estimated by the first position estimating unit 208. In areas where the detection unit detects vegetation, the automatic travel control unit 202 switches to controlling the lawn mower 10 by referring to the self-position estimated by the second position estimating unit 210. Therefore, in areas where it is considered difficult to estimate the self-position using a satellite positioning system, the sensor unit 27 can be used instead of the satellite positioning system to estimate the self-position. This can suppress a decrease in the accuracy of the self-position estimation.

[0106] Furthermore, the lawn mower 10 of this embodiment can identify the position of grass and trees using RGB image data and the height of grass and trees using orthophoto image data.

[0107] Modification

[0108] In the above-described embodiment, the detection unit 206 detects the place covered with grass and trees based on the RGB image data and the orthographic image data of the mowing period. However, the present application is not limited to this. For example, the place covered with grass and trees can also be detected by comparing the first image data taken in the first period and the second image data taken in the second period different from the first period. In this modification, as an example, the first period is set to the mowing period, and the second period is set to winter as a period in which grass and trees grow less than in the mowing period.

[0109] In this modification, an example in which both the first image data and the second image data are set to the orthographic image data is described.

[0110] Figure 9 is a side view schematically showing the travel road 60 in winter. In addition, Figure 9 The place shown in Figure 7 is the same place. As Figure 9 shown, it becomes a state in which the travel road 60 in the period grows almost no grass 70, 70A, 70B, and large grass 74. In addition, no leaves 72C grow on the branches 72B of the tree 72. In this modification, a plurality of aerial images, that is, the RGB image data (image data of the aerial image) of winter is taken, and is stored in the storage device 20D via the communication I / F 20E. The aerial images of winter are taken by flying a drone equipped with a camera to the upper space of the region shown in Figure 6 and photographing the region from each direction in winter. In addition, in this embodiment, as an example, the detection unit 206 transforms the plurality of aerial images of winter stored in the storage device 20D into the orthographic image data of winter including the point cloud data using a transformation tool such as Metashape (registered trademark) or the like.

[0111] On the other hand, a side view schematically showing the travel road 60 in the first period, that is, the mowing period is shown in Figure 7 As shown in the drawing, the travel road 60 in the period grows grass 70, 70A, 70B, and large grass 74. In addition, leaves 72C grow on the branches 72B of the tree 72. Also, as in winter, a plurality of aerial images, that is, the RGB image data (image data of the aerial image) of the mowing period is taken by flying a drone equipped with a camera to the upper space of the region shown in Figure 6 and photographing the region from each direction. The taken data is stored in the storage device 20D via the communication I / F 20E. In addition, in this embodiment, as an example, the detection unit 206 transforms the plurality of aerial images of the mowing period stored in the storage device 20D into the orthographic image data of the mowing period including the point cloud data using a transformation tool such as Metashape (registered trademark) or the like.

[0112] In this variation, detection unit 206 determines (estimates) the height of vegetation relative to the ground by comparing orthoimage data from the mowing season with orthoimage data from winter. By comparing orthoimage data from the mowing season with orthoimage data from winter, detection unit 206 estimates areas where objects exceeding a predetermined height relative to the ground exist as "areas with vegetation."

[0113] Thus, in the modified example, the detection unit 206 detects areas covered by vegetation by comparing orthoimage data acquired at different times. Therefore, the detection unit 206 can identify areas covered by vegetation on the travel path 60 based on the orthoimage data acquired at different times.

[0114] Furthermore, according to the modified example, an image of a location covered with vegetation and an image of a location not covered with vegetation can be acquired at a predetermined location on the travel road 60. Therefore, by comparing the images, the location covered with vegetation can be easily identified.

[0115] In the above embodiment, the lawn mower 10 is set to winter as the second period. However, the present invention is not limited thereto. For example, it can be a period other than winter when there are fewer plants than in the first period, or autumn, which is close to winter.

[0116] Furthermore, in the lawn mower 10 of the above-described embodiment, the automatic travel control unit 202 controls the lawn mower 10 by referring to the self-position estimated by the second position estimating unit 210 in the travel path 60 corresponding to the second self-position 64 and the third self-position 66. However, the present invention is not limited to this. The automatic travel control unit 202 may control the lawn mower 10 by referring to the self-position estimated by the second position estimating unit 210 only in the travel path 60 corresponding to the third self-position 66.

[0117] In the lawn mower 10 of the above-described embodiment, the sensor unit 27 is comprised of a three-axis acceleration sensor and a gyro sensor. However, the present invention is not limited to this. The sensor unit 27 may also be comprised of three acceleration sensors, each detecting acceleration along one of three different axes. Either configuration is acceptable. Furthermore, the sensor unit 27 may be configured to estimate the position of the lawn mower 10, as long as it is capable of estimating the position of the lawn mower 10. For example, it may be comprised of one or more of a plurality of sensors, including a rangefinder, a camera, a gyro sensor, a magnetic sensor, an acceleration sensor, and a radar sensor. With such a configuration, the position of the lawn mower 10 can be estimated based on information related to the position of the lawn mower 10.

[0118] In the above embodiment, the GPS device 26 is used as the satellite positioning system, but the present invention is not limited thereto. For example, a known technology such as the Global Navigation Satellite System (GNSS) or the Quasi-Zenith Satellite System (QZSS) can be used.

[0119] In the above-described embodiment, the rotating portion 14A of the crawler portion 14 is formed of a substantially right-angled triangular column. However, the present invention is not limited thereto. The crawler portion 14 may also be elliptical or circular, for example. The crawler portion 14 can be modified as appropriate.

[0120] In the above embodiment, the lawn mower 10 is configured as a four-wheel drive. However, the present invention is not limited thereto, and a two-wheel drive may also be employed.

[0121] In the above embodiment, crawler tracks 14 are used as the drive unit. However, the present invention is not limited to this. The drive unit may also be a wheel, for example. Furthermore, the lawn mower of the present invention is not limited to having four drive units; a structure with one drive unit each on the left and right sides may also be employed.

[0122] In addition, in the above-mentioned embodiment, Figure 4 The CPU 20A shown reads the software (program) and performs various processes other than the CPU. As examples of processors in this case, a programmable logic device (PLD) whose circuit structure can be changed after manufacturing, such as a field programmable gate array (FPGA), and an application-specific integrated circuit (ASIC), which is a processor having a circuit structure specifically designed to perform a specific process, i.e., a dedicated circuit, can be exemplified. In addition, each process can be performed by one of these various processors, or by a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs or a CPU and an FPGA). In addition, the hardware structure of these various processors is more specifically a circuit composed of a combination of circuit elements such as semiconductor elements.

[0123] In addition, each program described in the above embodiments can be provided in the form of a recording medium such as a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), or a Universal Serial Bus (USB) memory. Alternatively, the program can be provided in the form of a downloadable external device via a network.

[0124] As mentioned above, although one embodiment of the present invention has been described, it is needless to say that the present invention is not limited to the above and can be implemented in various modifications other than the above within the scope of the present invention.

Claims

1. A lawn mower comprising: The lawn mower body has a cutting blade for cutting grass; a first position estimating unit for estimating the position of the lawn mower body using a satellite positioning system; a second position estimating unit that estimates a position of the lawn mower body using a sensor unit provided on the lawn mower body; A detection unit detects areas covered by grass and trees on a pre-set driving path before mowing begins; and an automatic driving control unit that causes the lawn mower body to travel on the travel path with reference to the own position estimated by the first position estimating unit, and switches to causing the lawn mower body to travel with reference to the own position estimated by the second position estimating unit when the detection unit detects that the area is covered by the grass and trees. The detection unit is composed of: Acquire RGB image data having color information and orthophoto image data, wherein the orthophoto image data corresponds to a shooting area of ​​the RGB image data and includes point group data; determining the vegetation based on the color information in the RGB image data; and The height of the grass and trees is determined based on the height information of the point group data in the orthoimage data, thereby detecting a location covered by the grass and trees.

2. A lawn mower comprising: The lawn mower body has a cutting blade for cutting grass; a first position estimating unit for estimating the position of the lawn mower body using a satellite positioning system; a second position estimating unit that estimates a position of the lawn mower body using a sensor unit provided on the lawn mower body; A detection unit detects areas covered by grass and trees on a pre-set driving path before mowing begins; and an automatic driving control unit that causes the lawn mower body to travel on the travel path with reference to the own position estimated by the first position estimating unit, and switches to causing the lawn mower body to travel with reference to the own position estimated by the second position estimating unit when the detection unit detects that the area is covered by the grass and trees. The detection unit detects the area covered by the vegetation by comparing first image data and second image data, wherein the first image data includes an image of the travel path and is acquired at a first time period, and the second image data is acquired at a second time period different from the first time period. The first period is a mowing period; and The second period is a period when the grass and trees are less abundant than during the mowing period.

3. The lawn mower according to claim 1 or 2, wherein: The sensor unit includes one or more sensors selected from a range-finding sensor, a camera, a gyro sensor, a magnetic sensor, an acceleration sensor, and a radar sensor.

Images