Grass trimmer

Abstract

To provide a mower capable of reducing load on cutting blades while maintaining working efficiency.SOLUTION: A mower includes: a body part having a movement mechanism; cutting blades rotatably disposed on the body part; an imaging device disposed on the body part to image an image in a traveling direction; and a controller that, when height of grass in front of the body part is higher than a predetermined threshold, reduces traveling speed of the body part on the basis of information on the image imaged by the imaging device.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a grass cutter. [Background technology]

[0002] Patent Document 1 discloses a work vehicle for maintaining lawns. Specifically, the work vehicle in Patent Document 1 determines the stiffness of the lawn based on the activity of the lawn obtained from a leaf color meter, and rotates the cutting blade with a higher torque the higher the stiffness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-088252 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a grass cutter that cuts grass while moving, such as the work vehicle described in Patent Document 1, the load on the cutting blade increases when the diameter of the grass stalk is large. On the other hand, if the traveling speed is reduced in consideration of the load on the cutting blade, the work efficiency decreases.

[0005] An object of the present invention is to provide a grass cutter that can reduce the load on the cutting blade while maintaining working efficiency. [Means for solving the problem]

[0006] The grass cutter according to claim 1 has a main body with a movement mechanism, a cutting blade rotatably provided on the main body, an imaging device provided on the main body for capturing an image of the traveling direction, and a controller that reduces the traveling speed of the main body when the height of grass in front of the main body is higher than a predetermined threshold based on image information captured by the imaging device. The controller estimates a diameter of the grass stem based on the image information, and changes the running speed of the main body in accordance with the estimated diameter of the grass stem. .

[0007] In the grass cutter according to claim 1, the cutting blade is rotatably provided on the main body. Also, since the main body is equipped with a movement mechanism, the grass around the main body can be cut by rotating the cutting blade while moving the main body with the movement mechanism.

[0008] The main body is also provided with an imaging device that captures an image in the direction of travel, and a controller, and the controller reduces the running speed of the main body when the height of the grass in front of the main body is higher than a predetermined threshold based on image information captured by the imaging device. Generally, the taller the grass, the larger the diameter of the stem. Therefore, by reducing the running speed when the grass height is higher than the threshold, the load on the cutting blade can be reduced. Furthermore, when the grass height is equal to or less than the threshold, the grass is cut while maintaining the running speed, and therefore a decrease in work efficiency can be suppressed. Furthermore, by estimating the diameter of the grass stem based on the image information, even if the grass is tall, if the diameter of the stem is estimated to be small, the grass can be cut without reducing the traveling speed. Conversely, even if the grass is short, if the diameter of the stem is estimated to be large, the traveling speed can be reduced to minimize the load on the cutting blade.

[0009] The grass mower according to claim 2 is in accordance with claim 1, wherein the controller reduces the travel speed of the main body as the height of the grass increases.

[0010] In the grass cutter according to claim 2, the driving speed is reduced as the grass gets taller, so the driving speed does not have to be reduced all at once. This improves work efficiency compared to a configuration in which the driving speed is set to two stages, normal speed and low speed.

[0013] Claim 3 The grass mower according to claim 1 or 2 In the method, the controller reduces the rotation speed of the cutting blade when the height of the grass is higher than a predetermined threshold.

[0014] Claim 3 In the grass cutter according to the present invention, when the height of the grass is higher than a predetermined threshold, the travel speed is reduced and the rotation speed of the cutting blade is also reduced, thereby making it possible to further reduce the load on the cutting blade. Effect of the Invention

[0015] As described above, the grass cutter according to the present invention can reduce the load on the cutting blade while maintaining work efficiency. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a grass mower according to an embodiment. [Diagram 2] 1 is a side cross-sectional view showing a grass mower according to an embodiment in a partially broken state as viewed from the side. [Diagram 3] 1 is a block diagram showing a hardware configuration of a grass mower according to an embodiment. [Figure 4] 1 is a block diagram showing a functional configuration of a grass mower according to an embodiment. [Diagram 5] 5 is a flowchart showing an example of a flow of a motor control process in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A mower 10 according to an embodiment will be described with reference to the drawings. Note that the arrows UP, FR, and RH in the drawings respectively indicate the upward direction in the up-down direction, the forward direction in the front-rear direction, and the right direction in the left-right direction of the mower 10. Also, since the mower 10 is configured to be movable in both the forward and rearward directions, the forward direction does not necessarily coincide with the traveling direction.

[0018] As shown in FIGS. 1 and 2, the grass mower 10 of this embodiment mainly includes a main body 12, a cutting blade unit 14, and a control unit 16.

[0019] (Main body 12) The main body 12 is formed in a generally rectangular parallelepiped shape with an open bottom, and is provided with crawler units 18 as a movement mechanism on the main body 12. The crawler units 18 are provided on both the left and right sides of the front end of the main body 12 and on both the left and right sides of the rear end.

[0020] Each crawler section 18 includes a rubber crawler 18A, a driving 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 driving wheel 18B, the first idler wheel 18C, and the second idler wheel 18D.

[0021] The drive wheel 18B is connected via a rotating shaft (not shown) to a drive motor 35 (see FIG. 3) disposed inside the main body 12. The drive motor 35 is configured to receive power from a battery (not shown), and by supplying power to operate the drive motor 35, the drive wheel 18B rotates and the rubber crawler 18A moves so as to circulate in one direction.

[0022] The first idler wheel 18C is disposed forward and below the drive wheel 18B, and is rotatably attached to a rotating shaft (not shown) extending in the left-right direction. The first idler wheel 18C rotates following the movement of the rubber crawler 18A. The second idler wheel 18D is disposed rearward of the first idler wheel 18C, and is rotatably attached to a rotating shaft (not shown) extending in the left-right direction. The second idler wheel 18D rotates following the movement of the rubber crawler 18A.

[0023] Here, the drive motor 35 is provided independently for each of the four crawler units 18, and the grass mower 10 can be moved in any direction by controlling the four drive motors 35. For ease of explanation, the four drive motors 35 are illustrated together in FIG. 3.

[0024] A cover 20 is provided on the front surface of the main body 12. The cover 20 is a generally flat plate-like member with a plate thickness direction in the front-rear direction, and extends in the vertical and horizontal directions. The lower end of the cover 20 is located lower than the lower end of the main body 12, and the cover 20 narrows the gap between the main body 12 and the ground. The cover 20 prevents foreign objects such as stones from entering the cutting blade unit 14, which will be described later.

[0025] In this embodiment, as an example, the cover 20 is provided only on the front surface of the main body 12, but the present invention is not limited to this. For example, a similar cover 20 may be provided on the rear surface and side surface of the main body 12. Also, a member for preventing the intrusion of foreign matter similar to the cover 20 may be provided on both side surfaces of the main body 12.

[0026] (Blade unit 14) 2, the cutting blade unit 14 is provided inside the main body 12. The cutting blade unit 14 includes a rotating member 22, a cutting blade 24, a rotating shaft 26, and a cutting blade motor 28.

[0027] The rotating member 22 is disposed near the opening 12A on the lower side of the main body 12, with the thickness direction being the up-down direction. The rotating member 22 is fixed to a rotating shaft 26, which will be described later, and is configured to be rotatable with respect to the main body 12 together with the rotating shaft 26.

[0028] The rotating member 22 is provided with a plurality of cutting blades 24. The cutting blades 24 are attached to the outer peripheral end portion of the rotating member 22, and in the present embodiment, as an example, four cutting blades 24 are provided at equal intervals along the circumferential direction of the rotating member 22.

[0029] Each of the cutting blades 24 is formed from a thin metal member with its thickness direction extending in the vertical direction, and is configured to be able to cut grass.

[0030] The rotating shaft 26 is disposed in the center of the main body 12 and extends in the vertical direction, and the rotating member 22 is attached to the lower end of the rotating shaft 26. In addition, the upper end of the rotating shaft 26 is connected to a blade motor 28.

[0031] The blade motor 28 is attached to the upper part of the main body 12, and is driven by power supplied from a battery (not shown) provided in the main body 12. The blade motor 28 also has an output shaft (not shown), and this output shaft is connected to the rotating shaft 26 via a gear or pulley (not shown). Therefore, when the blade motor 28 is driven, a rotational force is transmitted to the rotating member 22 via the rotating shaft 26, and the rotating member 22 rotates in one direction around the rotating shaft 26.

[0032] As shown in FIGS. 1 and 2, the control unit 16 is provided on the upper surface of the main body 12, and includes a housing 16A having a substantially rectangular parallelepiped shape.

[0033] A GPS (Global Positioning System) device 32 is attached to the top surface of the housing 16A. The GPS device 32 is a device that measures the current position of the mower 10, and is configured to include an antenna (not shown) that receives signals from GPS satellites.

[0034] A camera unit 34 serving as an imaging device is attached to the front surface of the housing 16A. The camera unit 34 is a unit formed by combining a plurality of cameras, and is capable of capturing images of the surrounding conditions including the traveling direction of the mower 10. The control unit 16 is also provided with a controller 36.

[0035] (Hardware configuration of the grass cutter 10) Fig. 3 is a block diagram showing the hardware configuration of the grass mower 10. As shown in Fig. 3, the controller 36 constituting the grass mower 10 is configured to include a CPU (Central Processing Unit: processor) 38, a ROM (Read Only Memory) 40, a RAM (Random Access Memory) 42, a storage 44, a communication I / F (communication interface) 46, and an input / output I / F (input / output interface) 48. Each component is connected to each other via a bus 49 so as to be able to communicate with each other.

[0036] The CPU 38 is a central processing unit that executes various programs and controls each part. That is, the CPU 38 reads a program from the ROM 40 or the storage 44, and executes the program using the RAM 42 as a working area. The CPU 38 also controls each of the above components and performs various arithmetic processing according to the program recorded in the ROM 40 or the storage 44.

[0037] The ROM 40 stores various programs and various data. The RAM 42 is a non-temporary recording medium that temporarily stores programs or data as a working area. The storage 44 is a non-temporary recording medium that is configured with an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs including an operating system and various data. In this embodiment, the storage 44 stores the automatic driving program and various data of the grass mower 10.

[0038] The communication I / F 46 is an interface that enables the grass mower 10 to communicate with other devices, and uses standards such as CAN (Controller Area Network), Ethernet (registered trademark), LTE (Long Term Evolution), FDDI (Fiber Distributed Data Interface), and Wi-Fi (registered trademark).

[0039] The input / output I / F 48 is electrically connected to the GPS device 32, the camera unit 34, the drive motor 35, and the blade motor 28. The controller 36 controls the drive motor 35 based on images of the surroundings detected by the camera unit 34 and information such as the current position of the grass mower 10 acquired by the GPS device 32, thereby causing the grass mower 10 to travel automatically.

[0040] The controller 36 may automatically drive the grass mower 10 based on a driving plan for the grass mower 10 acquired from an external source and the remaining charge of a battery (not shown), etc.

[0041] (Functional configuration of the grass cutter 10) The grass mower 10 uses the above hardware resources to realize various functions. The functional configuration realized by the grass mower 10 will be described with reference to FIG.

[0042] 4, the grass mower 10 is configured to include, as functional components, an image information acquisition unit 50, a grass height calculation unit 52, a drive motor control unit 54, and a blade motor control unit 56. Each functional component is realized by the CPU 38 reading and executing a program stored in the ROM 40 or storage 44.

[0043] The image information acquisition section 50 acquires image information of the main body section 12 in the traveling direction captured by the camera unit 34 .

[0044] The grass height calculation unit 52 calculates the grass height of the grass detected on the planned travel route along which the main body unit 12 will travel, based on the image information acquired by the image information acquisition unit 50. Specifically, the grass on the planned travel route is detected from the image information, and the grass height is calculated by image processing. At this time, if sensors such as a gyro sensor and an acceleration sensor are installed, the attitude of the grass mower 10 can be detected, so that the grass height can be calculated with higher accuracy. In other words, even if the front part of the main body unit 12 is inclined upward or downward more than the rear part, the grass height can be calculated taking into account the inclination angle detected by the sensors.

[0045] The drive motor control unit 54 changes the running speed of the main body unit 12 by controlling the output of the drive motor 35 disposed inside the main body unit 12. In particular, the drive motor control unit 54 of this embodiment reduces the output of the drive motor 35 to reduce the running speed of the main body unit 12 when the grass height calculated by the grass height calculation unit 52 is higher than a predetermined first threshold value.

[0046] Furthermore, the drive motor control unit 54 of this embodiment reduces the travel speed of the main body 12 as the grass height increases. Specifically, the grass mower 10 has a table in which the relationship between the grass height and the output value of the drive motor 35 is set in advance, and the drive motor control unit 54 refers to the table to obtain the output of the drive motor 35 corresponding to the grass height calculated by the grass height calculation unit 52. Then, the drive motor control unit 54 changes the output of the drive motor 35 to the obtained output value.

[0047] The blade motor control unit 56 changes the rotation speed of the rotating member 22 by controlling the output of the blade motor 28. In other words, the blade motor control unit 56 changes the rotation speed of the blade 24 by controlling the output of the blade motor 28.

[0048] In particular, when the grass height calculated by the grass height calculation unit 52 is higher than a predetermined second threshold value, the blade motor control unit 56 of this embodiment reduces the output of the blade motor 28 to reduce the rotation speed of the blade 24. Moreover, the blade motor control unit 56 of this embodiment is configured to reduce the rotation speed of the blade 24 as the grass height increases.

[0049] (action) Next, the operation of this embodiment will be described.

[0050] (Motor control processing) 5 is a flowchart showing an example of the flow of a motor control process by the grass mower 10. This motor control process is executed by the CPU 38 reading a program from the ROM 40 or storage 44 and expanding the program in the RAM 42.

[0051] 5, the CPU 38 acquires image information in step S102. Specifically, the CPU 38 acquires image information of an image in the traveling direction of the main body 12 captured by the camera unit 34 using the function of the image information acquisition section 50.

[0052] In step S104, the CPU 38 determines whether the grass height is higher than the first threshold. Specifically, the CPU 38 calculates the grass height of the grass detected on the planned travel route along which the main body unit 12 will travel, based on the image information acquired by the image information acquisition unit 50 using the function of the grass height calculation unit 52. If the calculated grass height is higher than the preset first threshold, the process proceeds to step S106. On the other hand, if the grass height is equal to or less than the first threshold, the CPU 38 ends the motor control process. In other words, if the grass height is equal to or less than the first threshold, there is no need to change the output values ​​of the drive motor 35 and the blade motor 28, so the CPU 38 ends the motor control process.

[0053] In step S106, the CPU 38 determines whether or not the grass height is higher than a second threshold value. Here, the second threshold value is set to a value larger than the first threshold value.

[0054] When the grass height calculated by the grass height calculation unit 52 is higher than a preset second threshold, the CPU 38 proceeds to processing of step S110. On the other hand, when the grass height is equal to or less than the second threshold, the CPU 38 proceeds to processing of step S108. In other words, when the grass height is higher than the first threshold and equal to or less than the second threshold, the CPU 38 proceeds to processing of step S108.

[0055] The CPU 38 reduces the traveling speed in step S108. Specifically, the CPU 38 reduces the traveling speed of the main body 12 by reducing the output of the driving motor 35 using the function of the driving motor control unit 54. At this time, the CPU 38 reduces the traveling speed in stages according to the calculated grass height. Then, the CPU 38 ends the motor control process. Therefore, when the grass height is higher than the first threshold value and equal to or lower than the second threshold value, the rotation speed of the cutting blade 24 is not changed and only the traveling speed of the main body 12 is reduced.

[0056] On the other hand, if the grass height is higher than the second threshold, the CPU 38 reduces the traveling speed and the rotation speed in step S110. Specifically, the CPU 38 reduces the traveling speed of the main body 12 by reducing the output of the drive motor 35 using the function of the drive motor control unit 54, while reducing the rotation speed of the blade 24 by reducing the output of the blade motor 28 using the function of the blade motor control unit 56. At this time, the CPU 38 reduces the traveling speed and the blade speed in stages according to the calculated grass height. Then, the CPU 38 ends the motor control process.

[0057] As described above, in the mower 10 of this embodiment, the grass around the main body 12 can be cut by rotating the cutting blade 24 while moving the main body 12 by the crawler unit 18 serving as a movement mechanism.

[0058] Furthermore, in this embodiment, the grass mower 10 reduces the travel speed of the main body 12 when the height of the grass in front of the main body 12 is higher than a predetermined threshold based on image information captured by the camera unit 34. This reduces the load on the cutting blade 24. Furthermore, when the height of the grass is equal to or less than the threshold, the grass is cut while maintaining the travel speed, thereby preventing a decrease in work efficiency.

[0059] Furthermore, in this embodiment, the mower 10 reduces the travel speed as the grass height increases, so there is no need to reduce the travel speed all at once. This improves work efficiency compared to a configuration in which the travel speed is set to two stages, normal speed and low speed.

[0060] Furthermore, in this embodiment, when the grass height is higher than a predetermined second threshold, the traveling speed of the main body 12 is reduced, and the rotation speed of the cutting blade 24 is reduced. This makes it possible to further reduce the load on the cutting blade 24.

[0061] Although the mower 10 according to the embodiment has been described above, it is needless to say that the present invention can be embodied in various forms without departing from the scope of the present invention. In the above embodiment, the travel speed of the main body 12 and the rotation speed of the cutting blade 24 are changed in accordance with only the height of the grass, but the present invention is not limited to this. For example, the diameter of the grass stem may be estimated, and the travel speed of the main body 12 and the rotation speed of the cutting blade 24 may be changed in consideration of the estimated diameter of the grass stem.

[0062] Specifically, there is a method of adding a stem diameter estimation unit to the functional configuration of the grass mower 10. The stem diameter estimation unit identifies the type of grass detected on the planned travel route along which the main body unit 12 will travel, based on the image information acquired by the image information acquisition unit 50. For example, the type of grass is identified by referring to a pre-stored grass database and comparing it with the image information. The stem diameter estimation unit then estimates the stem diameter from the identified grass type. At this time, the stem diameter estimation unit may estimate the stem diameter taking into account the grass height calculated by the grass height calculation unit 52.

[0063] The drive motor control unit 54 controls the output value of the drive motor 35 based on the grass height calculated by the grass height calculation unit 52 and the stem diameter estimated by the stem diameter estimation unit. For example, the output value of the drive motor 35 may be determined by multiplying the output value of the drive motor 35 calculated according to the grass height by a predetermined coefficient based on the stem diameter.

[0064] In this way, by controlling the traveling speed based on the estimated stem diameter, even if the grass is tall, if the stem diameter is estimated to be small, the grass can be cut without reducing the traveling speed. Conversely, even if the grass is short, if the stem diameter is estimated to be large, the traveling speed can be reduced to minimize the load on the cutting blade.

[0065] In the above embodiment, the traveling speed of the main body 12 and the rotation speed of the cutting blade 24 are controlled, but the present invention is not limited to this, and it is also possible to control only the traveling speed of the main body 12.

[0066] Furthermore, the processing that the CPU 38 reads and executes the program in the above embodiment may be executed by various processors other than the CPU 38. Examples of the processor in this case include a PLD (Programmable Logic Device) whose circuit configuration can be changed after manufacture such as an FPGA (Field-Programmable Gate Array), and a dedicated electric circuit that is a processor having a circuit configuration designed exclusively for executing a specific process such as an ASIC (Application Spec Integrated Circuit). The above process may be executed by one of these various processors, or may be executed by a combination of two or more processors of the same or different types, for example, by multiple FPGAs, or a combination of a CPU and an FPGA. The hardware structure of these various processors is, more specifically, an electric circuit that combines circuit elements such as semiconductor elements.

[0067] Furthermore, in the above embodiment, various data are stored in the storage 44, but the present invention is not limited to this. For example, a non-transitory recording medium such as a CD (Compact Disk), a DVD (Digital Versatile Disk), or a USB (Universal Serial Bus) memory may be used as the storage unit. In this case, various programs and data are stored in these recording media.

[0068] Furthermore, the process flow described in the above embodiment is just an example, and unnecessary steps may be deleted, new steps may be added, or the process order may be changed, without departing from the spirit of the invention. [Explanation of symbols]

[0069] 10. Grass trimmer 12 Main body 14 Blade unit 18 Crawler section (movement mechanism) 20 Cover 22 Rotating members 24 cutting blade 34 Camera unit (imaging device) 36 Controller

Claims

1. A main body portion including a moving mechanism; A cutting blade rotatably provided on the main body portion; An imaging device provided in the main body for capturing an image in the traveling direction; a controller that reduces a traveling speed of the main body when a height of grass in front of the main body is higher than a predetermined threshold based on image information captured by the imaging device; having The controller estimates a diameter of a grass stem based on the image information, and changes the traveling speed of the main body in accordance with the estimated diameter of the grass stem.

2. The grass mower according to claim 1 , wherein the controller reduces the travel speed of the main body as the height of the grass increases.

3. A lawnmower as described in claim 1 or 2, wherein the controller reduces the rotational speed of the cutting blade when the height of the grass is higher than a predetermined threshold.

Images